new file: P13019.cpp

P13019.cpp

@@ -0,0 +1,61 @@
+#include<bits/stdc++.h>
+using namespace std;
+int n;
+vector<int> chi[100005];
+int fa[100005][25];
+int minc[100005][25];
+int q;
+int a;
+void pre(int now) {
+    for(int i = 1; i <= 20; ++i) {
+        fa[now][i] = fa[fa[now][i - 1]][i - 1];
+    }
+    for(int i : chi[now]) {
+        pre(i);
+    }
+    for(int i = 1; i <= 20; ++i) {
+        minc[now][i] = minc[minc[now][i - 1]][i - 1];
+    }
+}
+int main() {
+    scanf("%d%d", &n, &q);
+    fa[1][0] = 1;
+    for(int i = 2; i <= n; ++i) {
+        scanf("%d", &fa[i][0]);
+        chi[fa[i][0]].push_back(i);
+    }
+    for(int i = 1; i <= n; ++i) {
+        minc[i][0] = INT_MAX;
+        for(int j : chi[i]) {
+            minc[i][0] = min(minc[i][0], j);
+        }
+        if(minc[i][0] == INT_MAX) minc[i][0] = i;
+    }
+    pre(1);
+    while(q--) {
+        int s, k;
+        scanf("%d%d", &s, &k);
+        for(int i = 1; i <= k; ++i) {
+            scanf("%d", &a);
+            if(a > 0) {
+                for(int j = 20; j >= 0; --j) {
+                    if(a >= (1 << j)) {
+                        a -= (1 << j);
+                        s = fa[s][j];
+                    }
+                }
+            } else {
+                a = -a;
+                for(int j = 20; j >= 0; --j) {
+                    if(a >= (1 << j)) {
+                        a -= (1 << j);
+                        s = minc[s][j];
+                    }
+                }
+            }
+        }
+        // printf("111: %d\n", fa[5][0]);
+        printf("%d\n", s);
+    }
+    return 0;
+}