Fix rank + test

Author: adamant-pwn

cp-algo/linalg/matrix.hpp

@@ -151,10 +151,10 @@ namespace cp_algo::linalg {
         }
 
         size_t rank() const {
-            if(n() < m()) {
+            if(n() > m()) {
                 return T().rank();
             }
-            return size(matrix(*this).gauss()[0]);
+            return size(matrix(*this).echelonize()[0]);
         }
 
         base det() const {

verify/algebra/matrix/rank.test.cpp

@@ -0,0 +1,32 @@
+// @brief Rank of Matrix
+#define PROBLEM "https://judge.yosupo.jp/problem/matrix_rank"
+#pragma GCC optimize("Ofast,unroll-loops")
+#pragma GCC target("avx2,tune=native")
+#include "cp-algo/linalg/matrix.hpp"
+#include <bits/stdc++.h>
+
+using namespace std;
+using namespace cp_algo::algebra;
+using namespace cp_algo::linalg;
+
+const int mod = 998244353;
+using base = modular<mod>;
+
+void solve() {
+    int n, m;
+    cin >> n >> m;
+    matrix<base> A(n, m);
+    A.read();
+    cout << A.rank() << "\n";
+}
+
+signed main() {
+    //freopen("input.txt", "r", stdin);
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    int t = 1;
+    //cin >> t;
+    while(t--) {
+        solve();
+    }
+}