UVA1336FixingTheGreatWall

//UVA1336FixingTheGreatWall#include<cstdio>#include<cstring>#include<algorithm>#include<cmath>using namespace std;const int maxn = 1000 + 5;const double INF = 1e30;double sum_d[maxn], d[maxn][maxn][2];int n;char vis[maxn][maxn][2]; double v, x; struct tofix {double location, cost, delta;bool operator < (const tofix& rhs) const {    return location < rhs.location;}}fix[maxn];double spend(double x, double y, int i, int j) {double start = 0;if(i == 1 && j == n) return 0;if(i >= 0 && j >= 0) start += sum_d[j] - sum_d[i - 1]; return (sum_d[n] - start) * fabs(x - y) / v;} double dp(int i, int j, int k) {if(i == 1 && j == n) return 0;double& ans = d[i][j][k];if(vis[i][j][k]) return ans;vis[i][j][k] = true;ans = INF;double x = (k == 0) ? fix[i].location : fix[j].location;if(i > 1) ans = min(ans, dp(i - 1, j, 0) + spend(x, fix[i - 1].location, i, j));//向左走 if(j < n) ans = min(ans, dp(i, j + 1, 1) + spend(x, fix[j + 1].location, i, j));//向右走 return ans; }int main() {while(scanf("%d%lf%lf", &n, &v, &x) == 3 && n && v && x) {memset(vis, 0, sizeof(vis));memset(d, 0, sizeof(d));double tot = 0;for(int i = 1; i <= n; i++) {    scanf("%lf%lf%lf", &fix[i].location, &fix[i].cost, &fix[i].delta);     tot += fix[i].cost;}fix[0].location = -INF;fix[0].cost = fix[n + 1].cost = fix[0].delta = fix[n + 1].delta = 0;fix[n + 1].location = INF;sort(fix + 1, fix + n + 1);memset(sum_d, 0, sizeof(sum_d));for(int i = 1; i <= n; i++) sum_d[i] += sum_d[i - 1] + fix[i].delta; double ans = INF;for(int i = 1; i <= n + 1; i++) {if(fix[i - 1].location < x && fix[i].location > x) {//找到robot的初位置 if(i > 1) ans = min(ans, dp(i - 1, i - 1, 0) + spend(x, fix[i - 1].location, -1, -1));//决策，第一步向左走 if(i <= n) ans = min(ans, dp(i, i, 0) + spend(x, fix[i].location, -1, -1)); //同理于上 }}printf("%.0lf\n", floor(ans + tot));}return 0;} /*3 1 10001010 0 100998 0 300996 0 33 1 10001010 0 100998 0 3996 0 30 0 0*/