记忆化搜索 dp（dfs）-帮助Jimmy POJ--1661

不知道为什么编译器老说错。。。。

int n,x,y,maxx;
struct point{
    int l,r,h;
    bool friend operator<(point a,point b){
        return a.h<b.h;
    }
};
point node[mxn];
int dp[mxn][2];
int  dfs(int cur,int x,int time){
    if(node[cur].h==0)return time;
    if(dp[cur][0]!=inf||dp[cur][1]!=inf)return min(dp[cur][0],dp[cur][1]);
    int up=lower_bound(node,node+1+n,node[cur].h)-node;
    int down=lower_bound(node,node+1+n,node[cur].h-maxx)-node;
    int flagl=0,flagr=0;
    for(int i=up;i>=down;--i){
        if(node[cur].h-node[i].h>maxx)continue;
        if(node[cur].l<=node[i].l&&node[cur].l<=node[i].r&&!flagl){
           dp[cur][0]=min(dp[cur][0],dfs(i,node[cur].l,time+node[cur].h-node[cur].h+x-node[cur].l)); flagl=1;
        }
        if(node[cur].r<=node[i].l&&node[cur].r<=node[i].r&&!flagr){
            dp[cur][1]=min(dp[cur][1],dfs(i,node[cur].r,time+node[cur].h-node[cur].h+abs(x-node[cur].r)));flagr=1;
        }
    }
    return min(dp[cur][0],dp[cur][1]);
}
int main(){
    int T;sf("%d",&T);
    while(T--){
        sf("%d%d%d%d",&n,&x,&y,&maxx);
        mem(dp,inf);
        node[0].l=node[0].r=x;node[0].h=y;
        rep(i,1,n){
            sf("%d%d%d",&node[i].l,&node[i].r,&node[i].h);
        }
        node[n+1].l=0,node[n+1].r=0,node[n+1].h=0;
        sort(node,node+1+n);
        dfs(n+1,x,0);
        pf("%d\n",dp[0][0]);
    }
}