学步园

#include <cstring>
#include<cstdio>
#include<algorithm>
#include <cstdlib>
#include <iostream>
using namespace std;

const int maxn = 110000;

int total[maxn],disto[maxn],w[maxn],C,n,x[maxn],y[maxn],d[maxn];
int q[maxn];
int func(int j){
return d[j] - total[j+1] + disto[j+1];
}
int main()
{
    int T,kase;
    scanf("%d",&T);
    while(T--){
        if(kase++) printf("\n");
        scanf("%d %d",&C,&n);
        w[0]=total[0]=disto[0]=x[0]=y[0]=0;
        for(int i=1;i<=n;i++){
            int c;
            scanf("%d %d %d",&x[i],&y[i],&c);
            total[i]=total[i-1]+abs(x[i]-x[i-1])+abs(y[i]-y[i-1]);
            disto[i]=abs(x[i])+abs(y[i]);
            w[i]=w[i-1]+c;
        }
        q[1]=0;
        int front_,rear;
        front_=rear=1;
        for(int i=1;i<=n;i++){
            while(front_<=rear && w[i] - w[q[front_]] > C) front_++;
            d[i]=func(q[front_]) + total[i] + disto[i];
            while(front_<=rear && func(q[rear]) >= func(i) ) rear--;
            q[++rear]=i;
        }
        printf("%d\n",d[n]);
    }
    return 0;
}