prefer ranges algorithms over iterator-pair std calls (library + tests) (#244)

cameroncuster · web-flow · web-flow · commit a76ca2f847cc · 2026-07-12T12:50:20.000-07:00
* use ranges::iota over std::iota for full-range calls Convert the full-range std::iota(begin, end, v) calls to ranges::iota(range, v). This favors the ranges algorithms already used throughout the library and removes an all(...) macro expansion on main. Partial-range calls (e.g. iterator sub-ranges) and std::partial_sum are left as-is: partial_sum has no ranges equivalent, and partial ranges read more clearly with explicit iterators. * use ranges::unique and ranges::partition for full-range calls Convert the remaining full-range std algorithm calls to their ranges:: equivalents: - virtual_tree: unique(all(subset)) -> begin(ranges::unique(subset)) - edge_cd: partition(all(g[u]), ...) -> begin(ranges::partition(g[u], ...)) ranges::unique / ranges::partition return a subrange, so begin(...) yields the iterator the erase / offset logic needs. Partial-range calls (iterator sub-ranges) and std::partial_sum are still left as-is: partial_sum has no ranges equivalent, and partial ranges read more clearly with explicit iterators. * use ranges algorithms in tests for full-range std calls Apply the same "prefer ranges" convention to the test suite: - iota(all(x), v) -> ranges::iota(x, v) - unique(all(x)) -> begin(ranges::unique(x)) (erase / == end idiom) - remove_if(all(x), pred) -> begin(ranges::remove_if(x, pred)) (erase idiom) - next_permutation(all(x)) -> ranges::next_permutation(x).found accumulate(all(x), ...) is left as-is: there is no ranges::accumulate in C++23 (ranges::fold_left would change the idiom), matching how partial_sum is left in the library. * [auto-verifier] verify commit 69ac3da * [auto-verifier] verify commit e6325f1 --------- Co-authored-by: GitHub <noreply@github.com>
diff --git a/.verify-helper/timestamps.remote.json b/.verify-helper/timestamps.remote.json
diff --git a/library/dsu/line_tree.hpp b/library/dsu/line_tree.hpp
@@ -20,7 +20,7 @@ struct line_tree {
   vi p, last;
   vector<pii> edge;
   line_tree(int n): p(n, -1), last(n), edge(n, {-1, -1}) {
-    iota(all(last), 0);
+    ranges::iota(last, 0);
   }
   int size(int u) { return -p[f(u)]; }
   int f(int u) { return p[u] < 0 ? u : p[u] = f(p[u]); }
diff --git a/library/graphs/mst.hpp b/library/graphs/mst.hpp
@@ -10,7 +10,7 @@
 pair<ll, vi> mst(const vector<array<int, 3>>& w_eds,
   int n) {
   vi order(sz(w_eds));
-  iota(all(order), 0);
+  ranges::iota(order, 0);
   ranges::sort(order, {},
     [&](int i) { return w_eds[i][2]; });
   DSU dsu(n);
diff --git a/library/graphs/strongly_connected_components/offline_incremental_scc.hpp b/library/graphs/strongly_connected_components/offline_incremental_scc.hpp
@@ -14,7 +14,7 @@ vi offline_incremental_scc(vector<array<int, 2>> eds,
   int n) {
   int m = sz(eds);
   vi ids(n, -1), joins(m, m), idx(m), vs(n), scc_id;
-  iota(all(idx), 0);
+  ranges::iota(idx, 0);
   vector<vi> g;
   auto dnc = [&](this auto&& dnc, auto el, auto er, int tl,
                int tr) {
diff --git a/library/graphs/uncommon/complement_graph_ccs.hpp b/library/graphs/uncommon/complement_graph_ccs.hpp
@@ -12,7 +12,7 @@
 vi get_complement_graph_ccs(const auto& g) {
   int n = sz(g);
   vi cc_id(n), unseen(n);
-  iota(all(unseen), 0);
+  ranges::iota(unseen, 0);
   vector<bool> is_g(n);
   for (int cnt = 0; !empty(unseen); cnt++) {
     int s = unseen.back();
diff --git a/library/math/prime_sieve/calc_linear_sieve.hpp b/library/math/prime_sieve/calc_linear_sieve.hpp
@@ -2,7 +2,7 @@
 //! @time O(mx)
 //! @space O(mx)
 vi primes, sieve(1001); //!< min prime factor
-iota(all(sieve), 0);
+ranges::iota(sieve, 0);
 rep(i, 2, sz(sieve)) {
   if (sieve[i] == i) primes.push_back(i);
   for (int prime : primes) {
diff --git a/library/math/prime_sieve/calc_sieve.hpp b/library/math/prime_sieve/calc_sieve.hpp
@@ -2,7 +2,7 @@
 //! @time O(mx * log(log mx))
 //! @space O(mx)
 vi sieve(1001); //!< min prime factor
-iota(all(sieve), 0);
+ranges::iota(sieve, 0);
 for (int i = 2; i * i < sz(sieve); i++)
   if (sieve[i] == i)
     for (int j = i * i; j < sz(sieve); j += i)
diff --git a/library/strings/longest_common_subsequence/lcs_dp.hpp b/library/strings/longest_common_subsequence/lcs_dp.hpp
@@ -10,7 +10,7 @@
 template<class T> struct lcs_dp {
   T t;
   vi dp;
-  lcs_dp(const T& t): t(t), dp(sz(t)) { iota(all(dp), 0); }
+  lcs_dp(const T& t): t(t), dp(sz(t)) { ranges::iota(dp, 0); }
   void push_onto_s(int c) {
     int v = -1;
     rep(i, 0, sz(t)) if (c == t[i] || dp[i] < v)
diff --git a/library/strings/manacher/longest_palindrome_query.hpp b/library/strings/manacher/longest_palindrome_query.hpp
@@ -11,7 +11,7 @@ struct longest_pal_query {
   //! @space O(n log n) for rmq, everything else is O(n)
   longest_pal_query(const auto& s): man(manacher(s)) {
     vi init(sz(man));
-    iota(all(init), 0);
+    ranges::iota(init, 0);
     rmq = {init, [&](int i1, int i2) {
              return len(i1) < len(i2) ? i2 : i1;
            }};
diff --git a/library/strings/suffix_array/suffix_array.hpp b/library/strings/suffix_array/suffix_array.hpp
@@ -38,10 +38,10 @@
 auto get_sa(const auto& s, int max_num) {
   int n = sz(s);
   vi sa(n), sa_inv(all(s)), lcp(n - 1);
-  iota(all(sa), 0);
+  ranges::iota(sa, 0);
   for (int i = 0; i < n; i = max(1, 2 * i)) {
     vi y(sa_inv), freq(max_num);
-    iota(all(sa_inv), n - i);
+    ranges::iota(sa_inv, n - i);
     ranges::copy_if(sa, begin(sa_inv) + i,
       [&](int& x) { return (x -= i) >= 0; });
     for (int x : y) freq[x]++;
diff --git a/library/strings/suffix_array/suffix_array_short.hpp b/library/strings/suffix_array/suffix_array_short.hpp
@@ -14,7 +14,7 @@
 auto sa_short(const auto& s) {
   int n = sz(s), b = 6;
   vi sa(n), sa_inv(all(s)), lcp(n - 1), t(n);
-  iota(all(sa), 0);
+  ranges::iota(sa, 0);
   for (int j = 1; j <= n; j *= b) {
     swap(t, sa_inv);
     auto cmp = [&](int i1, int i2) {
diff --git a/library/trees/edge_cd.hpp b/library/trees/edge_cd.hpp
@@ -30,10 +30,10 @@ template<class G> void edge_cd(vector<G>& g, auto f) {
     if (m < 2) return;
     u = ctd(u, u, m);
     int sum = 0;
-    auto it = partition(all(g[u]), [&](int v) {
+    auto it = begin(ranges::partition(g[u], [&](int v) {
       ll x = sum + s[v];
       return x * x < m * (m - x) ? sum = x : 0;
-    });
+    }));
     f(u, it - begin(g[u]));
     G oth(it, end(g[u]));
     g[u].erase(it, end(g[u]));
diff --git a/library/trees/extra_members/virtual_tree.hpp b/library/trees/extra_members/virtual_tree.hpp
@@ -16,7 +16,7 @@ array<vi, 2> compress_tree(vi subset) {
   rep(i, 1, len)
     subset.push_back(lca(subset[i - 1], subset[i]));
   ranges::sort(subset, {}, proj);
-  subset.erase(unique(all(subset)), end(subset));
+  subset.erase(begin(ranges::unique(subset)), end(subset));
   return {
     mono_st(subset,
       [&](int u, int v) { return in_subtree(u, v); }),
diff --git a/tests/library_checker_aizu_tests/data_structures/bit_ordered_set.test.cpp b/tests/library_checker_aizu_tests/data_structures/bit_ordered_set.test.cpp
@@ -17,7 +17,7 @@ int main() {
     compress.push_back(x);
   }
   ranges::sort(compress);
-  compress.erase(unique(all(compress)), end(compress));
+  compress.erase(begin(ranges::unique(compress)), end(compress));
   BIT bit(sz(compress));
   auto get_compressed_idx = [&](int val) -> int {
     int l = 0, r = sz(compress);
diff --git a/tests/library_checker_aizu_tests/data_structures/kth_smallest_pst.test.cpp b/tests/library_checker_aizu_tests/data_structures/kth_smallest_pst.test.cpp
@@ -10,7 +10,7 @@ int main() {
   rep(i, 0, n) cin >> arr[i];
   vi sorted(arr);
   ranges::sort(sorted);
-  sorted.erase(unique(all(sorted)), end(sorted));
+  sorted.erase(begin(ranges::unique(sorted)), end(sorted));
   for (int& val : arr) {
     int start = 0, end = sz(sorted);
     while (start + 1 < end) {
diff --git a/tests/library_checker_aizu_tests/data_structures/mode_query.test.cpp b/tests/library_checker_aizu_tests/data_structures/mode_query.test.cpp
@@ -10,7 +10,7 @@ int main() {
   rep(i, 0, n) cin >> a[i];
   vi comp(a);
   ranges::sort(comp);
-  comp.erase(unique(all(comp)), end(comp));
+  comp.erase(begin(ranges::unique(comp)), end(comp));
   for (int& val : a) {
     int start = 0, end = sz(comp);
     while (start + 1 < end) {
diff --git a/tests/library_checker_aizu_tests/graphs/offline_incremental_scc.test.cpp b/tests/library_checker_aizu_tests/graphs/offline_incremental_scc.test.cpp
@@ -17,7 +17,7 @@ int main() {
   rep(t, 0, m)
     assert((eds[t][0] == eds[t][1]) == (joins[t] == -1));
   vi order(m);
-  iota(all(order), 0);
+  ranges::iota(order, 0);
   ranges::sort(order, {}, [&](int i) { return joins[i]; });
   DSU dsu(n);
   int sum = 0;
diff --git a/tests/library_checker_aizu_tests/handmade_tests/permutation_tree_small.test.cpp b/tests/library_checker_aizu_tests/handmade_tests/permutation_tree_small.test.cpp
@@ -7,10 +7,10 @@ int main() {
   cin.tie(0)->sync_with_stdio(0);
   for (int n = 1; n <= 8; n++) {
     vi a(n);
-    iota(all(a), 0);
+    ranges::iota(a, 0);
     do {
       perm_tree pt = perm_tree_asserts(a);
-    } while (next_permutation(all(a)));
+    } while (ranges::next_permutation(a).found);
   }
   cout << "Hello World\n";
   return 0;
diff --git a/tests/library_checker_aizu_tests/handmade_tests/rmq_small_n.test.cpp b/tests/library_checker_aizu_tests/handmade_tests/rmq_small_n.test.cpp
@@ -20,10 +20,10 @@ int main() {
   cin.tie(0)->sync_with_stdio(0);
   for (int n = 1; n <= 8; n++) {
     vi perm(n);
-    iota(all(perm), 0);
+    ranges::iota(perm, 0);
     do {
       test_all_subarrays(perm);
-    } while (next_permutation(all(perm)));
+    } while (ranges::next_permutation(perm).found);
   }
   for (int n = 1; n <= 100; n++) {
     rep(times, 0, 40) {
diff --git a/tests/library_checker_aizu_tests/handmade_tests/seg_tree_find.test.cpp b/tests/library_checker_aizu_tests/handmade_tests/seg_tree_find.test.cpp
@@ -51,7 +51,7 @@ int main() {
       else assert(cur_le == prv_ri);
     }
     ranges::sort(rngs);
-    assert(unique(all(rngs)) == end(rngs));
+    assert(begin(ranges::unique(rngs)) == end(rngs));
     reset();
     assert(
       pos == rv(rev.find_last(rv(r - 1), rv(l) + 1, f)));
@@ -67,7 +67,7 @@ int main() {
       else assert(prv_le == cur_ri);
     }
     ranges::sort(rngs);
-    assert(unique(all(rngs)) == end(rngs));
+    assert(begin(ranges::unique(rngs)) == end(rngs));
   }
   cout << "Hello World\n";
   return 0;
diff --git a/tests/library_checker_aizu_tests/mono_st_asserts.hpp b/tests/library_checker_aizu_tests/mono_st_asserts.hpp
@@ -11,7 +11,7 @@ tuple<int, vector<vi>, vi> min_cartesian_tree(const vi& a,
     return r[i] == n || a[r[i]] < a[i];
   };
   vi to_min(n);
-  iota(all(to_min), 0);
+  ranges::iota(to_min, 0);
   for (int i = n - 1; i >= 0; i--)
     if (!is_node(i)) to_min[i] = to_min[r[i]];
   vector<vi> adj(n);
diff --git a/tests/library_checker_aizu_tests/strings/sa_sort_pairs.test.cpp b/tests/library_checker_aizu_tests/strings/sa_sort_pairs.test.cpp
@@ -10,7 +10,7 @@ int main() {
   for (int& x : arr) cin >> x;
   vi compress(arr);
   ranges::sort(compress);
-  compress.erase(unique(all(compress)), end(compress));
+  compress.erase(begin(ranges::unique(compress)), end(compress));
   for (int& x : arr) {
     int l = -1, r = int(sz(compress));
     while (r - l > 1) {
@@ -24,7 +24,7 @@ int main() {
   auto [sa, sa_inv, lcp] = get_sa(arr, int(sz(compress)));
   sa_query lq(arr, sa, sa_inv, lcp);
   vi idxs(n);
-  iota(all(idxs), 0);
+  ranges::iota(idxs, 0);
   ranges::sort(idxs, [&](int i, int j) -> bool {
     return lq.cmp_substrs(2 * i, 2 * (i + 1), 2 * j,
              2 * (j + 1)) < 0;
diff --git a/tests/library_checker_aizu_tests/strings/single_matching_bs.test.cpp b/tests/library_checker_aizu_tests/strings/single_matching_bs.test.cpp
@@ -70,8 +70,8 @@ int main() {
       vi matches_other(begin(lq_both.sa) + sa_le2,
         begin(lq_both.sa) + sa_ri2);
       matches_other.erase(
-        remove_if(all(matches_other),
-          [&](int val) { return val >= sz(s) + 1; }),
+        begin(ranges::remove_if(matches_other,
+          [&](int val) { return val >= sz(s) + 1; })),
         end(matches_other));
       ranges::sort(matches_other);
       assert(matches == matches_other);

Original file line number	Diff line number	Diff line change
`@@ -20,7 +20,7 @@ struct line_tree {`
`20`	`20`	`vi p, last;`
`21`	`21`	`vector<pii> edge;`
`22`	`22`	`line_tree(int n): p(n, -1), last(n), edge(n, {-1, -1}) {`
`23`		`- iota(all(last), 0);`
	`23`	`+ ranges::iota(last, 0);`
`24`	`24`	`}`
`25`	`25`	`int size(int u) { return -p[f(u)]; }`
`26`	`26`	`int f(int u) { return p[u] < 0 ? u : p[u] = f(p[u]); }`