Gym 101667L Vacation Plans (dp)

吐槽题目有点长

一种贪心方法是错误的:时间越少越优,已经被样例否决

显然可以 (dp)

(dp[i][j][k]) 表示对于 (i) 人,它移动了 (k) 天到达了 (j) 的最小代价

然后暴力转移即可

但是这个移动了 (k) 天的这个 (k) 要开多大?

通过一系列的尝试确定大概 (2*10^5) 比较合适

然后就没了

注意开 (ll)

#include <map>
#include <set>
#include <ctime>
#include <queue>
#include <stack>
#include <cmath>
#include <vector>
#include <bitset>
#include <cstdio>
#include <cctype>
#include <string>
#include <numeric>
#include <cstring>
#include <cassert>
#include <climits>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <functional>
using namespace std ;
//#define int long long
#define rep(i, a, b) for (int i = (a); i <= (b); i++)
#define per(i, a, b) for (int i = (a); i >= (b); i--)
#define loop(s, v, it) for (s::iterator it = v.begin(); it != v.end(); it++)
#define cont(i, x) for (int i = head[x]; i; i = e[i].nxt)
#define clr(a) memset(a, 0, sizeof(a))
#define ass(a, sum) memset(a, sum, sizeof(a))
#define lowbit(x) (x & -x)
#define all(x) x.begin(), x.end()
#define ub upper_bound
#define lb lower_bound
#define pq priority_queue
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define iv inline void
#define enter cout << endl
#define siz(x) ((int)x.size())
#define file(x) freopen(#x".in", "r", stdin),freopen(#x".out", "w", stdout)
typedef long long ll ;
typedef unsigned long long ull ;
typedef pair <int, int> pii ;
typedef vector <int> vi ;
typedef vector <pii> vii ;
typedef queue <int> qi ;
typedef queue <pii> qii ;
typedef set <int> si ;
typedef map <int, int> mii ;
typedef map <string, int> msi ;
const int N = 210 ;
const int T = 200000 ;
const int INF = 0x3f3f3f3f ;
const int iinf = 1 << 30 ;
const ll linf = 1000000000000000000ll ;
const int MOD =  1e9 + 7 ;
const double eps = 1e-7 ;
void print(int x) { cout << x << endl ; exit(0) ; }
void PRINT(string x) { cout << x << endl ; exit(0) ; }
void douout(double x){ printf("%lf
", x + 0.0000000001) ; }
template <class T> void chmin(T &a, T b) { if (a > b) a = b ; }
template <class T> void chmax(T &a, T b) { if (a < b) a = b ; }
template <class T> void upd(T &a, T b) { (a += b) %= MOD ; }
template <class T> void mul(T &a, T b) { a = 1ll * a * b % MOD ; }

int x[N], y[N], d[N], h[60], t[5] ;
ll f[5][60][T + 10] ;
int n, m, q ;

signed main() {
	scanf("%d", &q) ;
	rep(i, 1, 3)
	rep(j, 1, 50)
	rep(k, 0, T)
	f[i][j][k] = linf ;
	rep(id, 1, q) {
		scanf("%d%d", &n, &m) ;
		rep(i, 1, n) scanf("%d", &h[i]) ;
		rep(i, 1, m) scanf("%d%d%d", &x[i], &y[i], &d[i]) ;
		scanf("%d", &t[id]) ;
		f[id][1][0] = 0 ;
		rep(i, 0, T) {
			rep(j, 1, n)
		//	if (f[id][j][i] != linf)
			f[id][j][i + 1] = min(f[id][j][i + 1], f[id][j][i] + h[j]) ;
			// 住
			rep(k, 1, m)
		//	if (f[id][x[k]][i] != linf)
			f[id][y[k]][i + 1] = min(f[id][y[k]][i + 1], f[id][x[k]][i] + d[k]) ;
			// 走
		}
	}
	ll ans = linf ;
	rep(i, 0, T) {
		ll cur = 0 ;
		rep(id, 1, q) cur += f[id][t[id]][i] ;
		ans = min(ans, cur) ;
	}
	printf("%lld
", ans) ;
	return 0 ;
}

/*
写代码时请注意:
    1.ll?数组大小,边界?数据范围?
    2.精度?
    3.特判?
    4.至少做一些
思考提醒:
    1.最大值最小->二分?
    2.可以贪心么?不行dp可以么
    3.可以优化么
    4.维护区间用什么数据结构?
    5.统计方案是用dp?模了么?
    6.逆向思维?(正難則反)
*/


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原文地址:https://www.cnblogs.com/harryhqg/p/10554471.html