兩道初級樹形DP

/* * Anniversary_party.c * *  Created on: 2012-3-13 *      Author: timest */#define DEBUG#include <stdio.h>#include <stdlib.h>#define MAX 6001int max(int a, int b){return a > b? a : b;}enum bool{false,true};int n;int dp[MAX][2];int value[MAX];int p[MAX];void dfs(int root){int leaf = true;int dp0 = 0,dp1 = 0;for(int i = 1; i <= n; i++) {if(p[i] == root){//有孩子leaf = false;dfs(i);dp0 += max(dp[i][1], dp[i][0]);dp1 += dp[i][0];}}if(leaf == true){dp[root][0] = 0;dp[root][1] = value[root];}else{dp[root][0] = dp0;dp[root][1] = dp1 + value[root];}}int main(){#ifdef DEBUGfreopen("/tmp/in","r",stdin);#endifwhile(scanf("%d",&n)!=EOF){for(int i = 1; i <= n; i++) {scanf("%d",&value[i]);}for(int i = 1; i <= n; i++) {p[i] = -1;}int a,b;int sum = 0;while(scanf("%d%d",&a,&b),a,b){p[a] = b; //a的父節點是b}for(int i=1; i <= n; i++) {if(p[i]==-1){ // i節點沒有父親dfs(i);sum += max(dp[i][0], dp[i][1]);}}printf("%d\n",sum);}return 0;}

題目連結：http://acm.hdu.edu.cn/showproblem.php?pid=1520

#define DEBUG#define true 1#define false 0#define bool int#include <stdio.h>#include <stdlib.h>#include <string.h>#include <memory.h>#define MAX 1500int p[MAX], n ;int dp[MAX][2];int min(int a, int b){return a  > b ? b : a;}void dfs(int root){bool leaf = true; //判斷是否為葉子節點int dp1 = 0, dp0 = 0;for(int i = 0; i < n; i++) {if(p[i] == root){leaf = false;dfs(i);dp1 += min(dp[i][0], dp[i][1]);dp0 += dp[i][1];}}//如果是葉子節點if(leaf) {dp[root][0] = 0;dp[root][1] = 1;}else {dp[root][0] = dp0;dp[root][1] = dp1 + 1;}}int main() {#ifdef DEBUGfreopen("/tmp/in", "r", stdin);#endifint t,m,s;while(scanf("%d",&n)!=EOF && n!=0) {for(int i=0; i < n; i++)p[i] = -1; //-1 表示 根節點for(int i=0; i < n; i++){scanf("%d:(%d)",&t,&m);for(int j = 0; j < m; j++){scanf("%d",&s);p[s] = t; //s節點的父節點是i}}for(int i = 0; i < n; i++) {if(p[i]==-1){dfs(i);printf("%d\n",min(dp[i][0],dp[i][1]));break;}}}return 0;}

題目連結：http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=1134