Add compress coords util

Author: adamant-pwn

cp-algo/util/compress_coords.hpp

@@ -0,0 +1,23 @@
+#ifndef CP_ALGO_UTIL_COMPRESS_COORDS_HPP
+#define CP_ALGO_UTIL_COMPRESS_COORDS_HPP
+#include <algorithm>
+#include <vector>
+namespace cp_algo {
+    std::vector<int> compress_coords(auto &coords) {
+        static_assert(std::is_pointer_v<std::ranges::range_value_t<decltype(coords)>>);
+        std::vector<int> original;
+        original.reserve(size(coords));
+        std::ranges::sort(coords, {}, [](int* x) {return *x;});
+        int idx = -1, prev = -1;
+        for(auto x: coords) {
+            if(*x != prev) {
+                idx++;
+                prev = *x;
+                original.push_back(*x);
+            }
+            *x = idx;
+        }
+        return original;
+    }
+}
+#endif // CP_ALGO_UTIL_COMPRESS_COORDS_HPP

verify/structures/fenwick/ordered_set.test.cpp

@@ -2,26 +2,12 @@
 #define PROBLEM "https://judge.yosupo.jp/problem/ordered_set"
 #pragma GCC optimize("Ofast,unroll-loops")
 #include "cp-algo/structures/fenwick_set.hpp"
+#include "cp-algo/util/compress_coords.hpp"
 #include <bits/stdc++.h>
 
 using namespace std;
 using cp_algo::structures::fenwick_set;
 
-vector<int> compress(vector<int*> a) {
-    vector<int> nums;
-    ranges::sort(a, {}, [](int* x) {return *x;});
-    int idx = -1, prev = -1;
-    for(auto x: a) {
-        if(*x != prev) {
-            idx++;
-            prev = *x;
-            nums.push_back(*x);
-        }
-        *x = idx;
-    }
-    return nums;
-}
-
 void solve() {
     int n, q;
     cin >> n >> q;
@@ -38,7 +24,7 @@ void solve() {
             coords.push_back(&x);
         }
     }
-    auto nums = compress(coords);
+    auto values = cp_algo::compress_coords(coords);
     const int maxc = 1e6;
     fenwick_set<maxc> me(a);
     for(auto [t, x]: queries) {
@@ -48,15 +34,15 @@ void solve() {
             me.erase(x);
         } else if(t == 2) {
             int res = me.find_by_order(x-1);
-            cout << (res == -1 ? -1 : nums[res]) << '\n';
+            cout << (res == -1 ? -1 : values[res]) << '\n';
         } else if(t == 3) {
             cout << me.order_of_key(x+1) << '\n';
         } else if(t == 4) {
             int res = me.pre_upper_bound(x);
-            cout << (res == -1 ? -1 : nums[res]) << '\n';
+            cout << (res == -1 ? -1 : values[res]) << '\n';
         } else if(t == 5) {
             int res = me.lower_bound(x);
-            cout << (res == -1 ? -1 : nums[res]) << '\n';
+            cout << (res == -1 ? -1 : values[res]) << '\n';
         }
     }
 }