ch_5201 数字组合
01背包
#include<iostream> #include<cstdio> #define ri register int #define u int namespace opt { inline u in() { u x(0),f(1); char s(getchar()); while(s<'0'||s>'9') { if(s=='-') f=-1; s=getchar(); } while(s>='0'&&s<='9') { x=(x<<1)+(x<<3)+s-'0'; s=getchar(); } return x*f; } } using opt::in; #define NN 105 #define MM 10005 #include<algorithm> namespace mainstay { u N,M,a[NN],f[MM]={1}; inline void solve() { std::cin>>N>>M; for(ri i(1);i<=N;++i) std::cin>>a[i]; for(ri i(1);i<=N;++i){ for(ri j(M);j>=a[i];--j){ f[j]+=f[j-a[i]]; } } std::cout<<f[M]; } } int main() { //freopen("x.txt","r",stdin); std::ios::sync_with_stdio(false); mainstay::solve(); }