[2016-03-29][POJ][1661][]Help Jimmy]

• 时间:2016-03-29 21:36:50 星期二

• 题目编号:[2016-03-29][POJ][1661][]Help Jimmy]

#include <algorithm>
#include <cstring>
#include <cstdio>
using namespace std;
int n,x,y,maxh;
struct Plat{
        int l,r,h;
        bool operator < (const Plat & a)const{
                return h < a.h;
        }
        Plat(int _l = 0,int _r = 0,int _h = 0):l(_l),r(_r),h(_h){}
        int canFallOn(int _x,int _h){
                return _x >= l && _x <= r && _h >= h && (_h - h) <= maxh;
        }
}a[1000 + 10];
int dp[1000 + 10][2];
void toleft(int i){
        for(int k = i - 1;k > 0;--k){
                if(a[k].canFallOn(a[i].l,a[i].h)){
                        dp[i][0] = a[i].h - a[k].h +   min (a[i].l - a[k].l + dp[k][0], a[k].r - a[i].l + dp[k][1]);
                        return ;
                }
        }
        if(a[i].h - a[0].h > maxh) 
                dp[i][0] = 0x7f7f7f7f; 
        else  dp[i][0] = a[i].h; 
}
void toright(int i){
        for(int k = i - 1;k > 0;--k){
                if(a[k].canFallOn(a[i].r,a[i].h)){
                        dp[i][1] = a[i].h - a[k].h +   min (a[i].r - a[k].l + dp[k][0], a[k].r - a[i].r + dp[k][1]);
                        return ;
                }
        }
        if(a[i].h - a[0].h > maxh) 
                dp[i][1] = 0x7f7f7f7f; 
        else  dp[i][1] = a[i].h; 
}
void dfs(){
        Plat tmp(x,x,y);
        a[0] = tmp;
        a[n + 1] = Plat(-20010,20010,0);
        sort(a,a + n + 2);
        for(int i = 1 ;i <= n + 1 ;++i){
                toleft(i);
                toright(i);               
        }
        printf("%d\n",min(dp[n + 1][0],dp[n + 1][1]));
}
int main(){
        int t;
        scanf("%d",&t);
        while(t--){
                scanf("%d%d%d%d",&n,&x,&y,&maxh);
                for(int i = 1 ; i <= n ; ++i){
                        scanf("%d%d%d",&a[i].l ,&a[i].r,&a[i].h );
                }               
                dfs();               
        }
        return 0;
}

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