upload some new code

FZOI/「模板」PYB的高斯消元.cpp

@@ -0,0 +1,50 @@
+#include <bits/stdc++.h>
+#define int long long
+#define endl "\n"
+#define IMX LONG_LONG_MAX
+#define IMN LONG_LONG_MIN
+#define debug$ if(dev)
+using namespace std;
+
+/* toothless. #17 */
+
+const int N = 1e7 + 10;
+const int M = 2e3 + 5;
+const bool dev = false;
+
+int n; 
+double a[M][M];
+
+signed main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    cout.tie(0);
+    cin >> n;
+    for (int i = 1; i <= n; i++) {
+        for (int j = 1; j <= n + 1; j++) cin >> a[i][j];
+    }
+    for (int i = 1; i <= n; i++) {
+        int flag = 1;
+        for (int j = i; j <= n; j++)
+        {
+            if (fabs(a[j][i]) > 1e-8) {
+                flag = 0;
+                for (int k = 1; k <= n + 1; k ++ ) swap(a[i][k], a[j][k]);
+                break;
+            }
+        }
+        if (flag) {
+            cout << "No Solution" << endl ;
+            return 0;
+        }
+        for (int j = 1; j <= n; j++) {
+            if (i != j) {
+                double rate = a[j][i] / a[i][i];
+                for (int k = i; k <= n + 1; k++) a[j][k] -= a[i][k] * rate;
+            }
+        }
+    }
+    for (int i = 1; i <= n; i++) printf("%.2lf\n", a[i][n + 1] / a[i][i]);
+    return 0;
+}