洛谷P3112 [USACO14DEC]后卫马克Guard Mark

 1 #include <bits/stdc++.h>
 2 #define For(i,j,k) for(int i=j;i<=k;i++) 
 3 #define LL long long 
 4 using namespace std ; 
 5 
 6 const int N = 21 ; 
 7 int n,H,res ; 
 8 LL sum ; 
 9 int dp[1100000],bin[21] ;  
10 struct cow{
11     int height,weight,pow ; 
12 }a[N];
13 
14 inline int read() 
15 {
16     int x = 0 , f = 1 ; 
17     char ch = getchar() ; 
18     while(ch<‘0‘||ch>‘9‘) { if(ch==‘-‘) f = -1 ; ch = getchar() ; } 
19     while(ch>=‘0‘&&ch<=‘9‘) { x = x * 10+ch-48 ; ch = getchar() ; } 
20     return x * f ;  
21 }
22 
23 int main() 
24 {
25     n = read() ; H = read() ; 
26     res = -1 ; 
27     For(i,1,n) {
28         a[i].height = read() ; a[i].weight = read() ; a[i].pow = read() ; 
29     }
30     memset(dp,-1,sizeof dp) ; 
31     bin[0] = 1 ; 
32     For(i,1,n) bin[i]=bin[i-1]*2 , dp[bin[i-1]] = a[i].pow ; 
33     For(i,1,bin[n]-1) {
34       For(j,1,n)    
35         if(!(i & bin[j-1])) 
36             dp[i | bin[j-1] ] = max(dp[i | bin[j-1] ],min(dp[i]-a[j].weight,a[j].pow) ) ;  
37       sum = 0 ; 
38       For(j,1,n) 
39           if(i & bin[j-1] ) sum=sum+ a[j].height ; 
40       if(sum>=H) 
41           if(res<dp[i])
42               res = dp[ i ] ; 
43     }
44     if(res>=0) printf("%d\n",res) ; 
45     else printf("Mark is too tall") ; 
46     return 0 ; 
47 }