• 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)
    */
    
    
    
    加油ヾ(◍°∇°◍)ノ゙
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  • 原文地址:https://www.cnblogs.com/harryhqg/p/10554471.html
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