hdu6024 Building Shops(区间dp)

https://cn.vjudge.net/problem/HDU-6024

分开考虑某一点种与不种，最后取二者的最小值。

dp[i][1] = min(dp[i-1][0], dp[i-1][1])+c[i];

dp[i][0]则是j从i-1~1递减，判断当j种是，i的最小值，然后取总的最小。

注意dp初始化为INF，以及要开long long

 #include<iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<cstdlib>
 #include<cmath>
 #define lson l, m, rt<<1
 #define rson m+1, r, rt<<1|1
 #define IO ios::sync_with_stdio(false);cin.tie(0);
 #define INF 1e9
 typedef long long ll;
 using namespace std;
 int n, m;
 ll dp[][];
 typedef struct {
     ll x, c;
 }Node;
 Node node[];
 bool cmp(const Node a, const Node b)
 {
     return a.x<b.x;
 }
 int main()
 {
     while(cin >> n){
         for(int i = ; i <= n; i++){
             cin >> node[i].x >> node[i].c;
         }
         for(int i = ; i <= n; i++){
             dp[i][] = INF;
             dp[i][] = INF;
         }
         dp[][]=;dp[][]=;
         sort(node+, node+n+, cmp);
         for(int i = ; i <= n; i++){
             dp[i][] = min(dp[i-][], dp[i-][])+node[i].c;
             ll tmp = ;
             for(int j = i-; j >= ; j--){
                 tmp += (i-j)*(node[j+].x - node[j].x);//次数*长度
                 dp[i][] = min(dp[i][], dp[j][]+tmp);
             }
         }
         cout << min(dp[n][], dp[n][]) << endl;
     }
     return ;
 }