poj 1011 Sticks (DFS)

来源：互联网发布：win10怎么重置网络设置编辑：程序博客网时间：2024/06/10 16:27
思路：深搜就可以了。
代码：
#include<stdio.h>#include<string.h>#include<algorithm>#include<cstdio>#include<iostream>using namespace std;int n , length[70];int used[70];int len;int inf = 0x3f3f3f3f;int min , maxn;int t;bool flag;bool cmp(const int a, const int b){    return a > b;}void dfs(int i , int l , int tot){    if(flag) return ;    //printf("i = %d , l = %d , tot = %d\n" , i , l , tot);    if(l == 0){        tot -= len;        if(tot == 0){            flag = true;            printf("%d\n" ,len);            return;        }        else if(tot < 0){            return;        }        else{            for(i = 0 ; used[i] ; ++i);            used[i] = 1;            dfs(i + 1 , len - length[i] , tot);            used[i] = 0;        }    }    else{        for(int j = i ; j < n ; j++){            //printf("j - 1 = %d\n" , j - 1);            if(length[j] == length[j - 1] && !used[j - 1]) continue;            if(!used[j] && l >= length[j]) {                used[j] = 1;                dfs(j , l - length[j] , tot);                used[j] = 0;            }        }    }    return ;}int main(){    while(~scanf("%d" , &n) && n != 0){        maxn = -inf;        t = 0;        flag = false;        memset(used , 0 , sizeof(used));        for(int i = 0 ; i < n ; i ++){            scanf("%d" , &length[i]);            if(maxn < length[i]){                maxn = length[i];            }            t += length[i];        }        sort(length , length + n , cmp);        for(len = length[0] ; len <= t / 2 ; ++len) {            if(flag) break;            if(t % len == 0){                flag = false;                dfs(0 , len , t);            }        }        if(!flag)            printf("%d\n" , t);    }    return 0;}