'commit'

TangDou/AcWing/Test/Test.cpp

@@ -0,0 +1,36 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+const int N = 100010;
+int b[N], in[N];
+
+int main() {
+    int n, m;
+    cin >> n >> m;
+    for (int i = 1; i <= n; i++) {
+        int x, y;
+        cin >> x >> y;
+        in[y]++;
+        b[x] = y;
+    }
+    int head = 0;
+    for (int i = 1; i <= n; i++)
+        if (in[i] == 0) {
+            head = i;
+            break;
+        }
+    for (int i = 1; i <= m; i++) {
+        int x, y;
+        cin >> x >> y;
+        int t = b[x];
+        b[x] = y;
+        b[y] = t;
+    }
+    cout << head << endl;
+    int x = b[head];
+    while(x){
+        cout << x << endl;
+        x = b[x];
+    }
+    return 0;
+}