2014 Super Training #2 C Robotruck --單調隊列最佳化DP

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原題： UVA 1169  http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=3610

大白書上的原題。

 

代碼：

#include <iostream>#include <cstdio>#include <cstring>#include <cmath>#include <algorithm>using namespace std;#define N 100007int dp[N],T[N];int dis[N],wt[N];int que[N];struct Point{    int x,y,w;}p[N];int f(int j){    return dp[j]-T[j+1]+dis[j+1];}int DIS(int i,int j){    return abs(p[i].x-p[j].x) + abs(p[i].y-p[j].y);}int main(){    int t,C,n,i,j;    scanf("%d",&t);    while(t--)    {        scanf("%d",&C);        scanf("%d",&n);        memset(que,0,sizeof(que));        wt[0] = 0;        T[0] = 0;        p[0].x = p[0].y = p[0].w = 0;        for(i=1;i<=n;i++)        {            scanf("%d%d%d",&p[i].x,&p[i].y,&p[i].w);            wt[i] = wt[i-1] + p[i].w;            T[i] = T[i-1] + DIS(i,i-1);            dis[i] = DIS(i,0);        }        int head = 0;        int tail = 0;        for(i=1;i<=n;i++)        {            while(head <= tail && wt[i]-wt[que[head]] > C)                head++;            dp[i] = f(que[head]) + T[i] + dis[i];            int fi = f(i);            while(head <= tail && fi <= f(que[tail]))                tail--;            que[++tail] = i;        }        printf("%d\n",dp[n]);        if(t)            puts("");    }    return 0;}

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