HDU 2141 Can you find it? [二分]
Can you find it?
Give you three sequences of numbers A, B, C, then we give you a number X. Now you need to calculate if you can find the three numbers Ai, Bj, Ck, which satisfy the formula Ai+Bj+Ck = X.
你以为我是因为被$world final$打击到了而在做水题吗?
没错我就是在做水题.........mhy12345课件上的.....
每个询问枚举$A$然后二分$B+C$
#include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #include<cmath> using namespace std; const int N=505,M=N*N; inline int read(){ char c=getchar();int x=0,f=1; while(c<'0'||c>'9'){if(c=='-')f=-1; c=getchar();} while(c>='0'&&c<='9'){x=x*10+c-'0'; c=getchar();} return x*f; } int a[N],b[N],c[N]; int w[M],n; int Bin(int v){//printf("Bin %d\n",v); int l=1,r=n; while(l<=r){ int mid=(l+r)>>1;//printf("%d %d %d %d %d\n",l,r,mid,w[mid],v); if(w[mid]==v) return mid; else if(v<w[mid]) r=mid-1; else l=mid+1; } return 0; } int main(){ freopen("in","r",stdin); int cas=0; while(scanf("%d%d%d",a,b,c)!=EOF){ printf("Case %d:\n",++cas); for(int i=1;i<=(*a);i++) a[i]=read(); for(int i=1;i<=(*b);i++) b[i]=read(); for(int i=1;i<=(*c);i++) c[i]=read(); n=0; for(int i=1;i<=(*b);i++) for(int j=1;j<=(*c);j++) w[++n]=b[i]+c[j]; sort(w+1,w+1+n); int Q=read(); while(Q--){ int x=read(),flag=0; for(int i=1;i<=(*a);i++) if(Bin(x-a[i])) {flag=1;break;} if(flag) puts("YES"); else puts("NO"); } } }
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