add PARADOX

paradox.cpp

@@ -0,0 +1,39 @@
+// 2016-04-28
+#include <cstdio>
+#include <vector>
+using namespace std;
+int main() {
+    int N;
+    for (;;) {
+        scanf("%d", &N);
+        if (!N) return 0;
+        vector<vector<char>> adj(2*N, vector<char>(2*N));
+        for (int i = 0; i < N; i++) {
+            int j; char s[10];
+            scanf("%d %s", &j, s); j--;
+            if (s[0] == 't') {
+                adj[i][j] = true; adj[j+N][i+N] = true;
+                adj[i+N][j+N] = true; adj[j][i] = true;
+            } else {
+                adj[i][j+N] = true; adj[j][i+N] = true;
+                adj[i+N][j] = true; adj[j+N][i] = true;
+            }
+        }
+        for (int k = 0; k < 2*N; k++) {
+            for (int i = 0; i < 2*N; i++) {
+                for (int j = 0; j < 2*N; j++) {
+                    adj[i][j] |= adj[i][k] && adj[k][j];
+                }
+            }
+        }
+        bool paradox = false;
+        for (int i = 0; i < N; i++) {
+            paradox |= adj[i][i+N];
+        }
+        if (paradox) {
+            puts("PARADOX");
+        } else {
+            puts("NOT PARADOX");
+        }
+    }
+}