A
#include <iostream>#include <cstring>#include <cstdio>#include <algorithm>#include <map>#include <set>#include <vector>using namespace std;int A[50];int main(){int n; string s;cin>>n;cin>>s;memset(A,0,sizeof(A));for(int i=0;i<n;i++){int c;if(s[i] >= 'A' && s[i] <= 'Z')c = s[i] – 'A';else if(s[i] >= 'a' && s[i] <='z') c = s[i] – 'a';A[c] = 1;}int flag = true;for(int i=0;i<26;i++) if(A[i] == 0){flag = false;break;}if(flag) cout<<"YES"<<endl;else cout<<"NO"<<endl;return 0;}
B
/* ***********************************************Author:moguCreated Time :2015/3/9 10:17:30File Name:************************************************ */#include <iostream>#include <algorithm>#include <vector>#include <queue>#include <set>#include <map>#include <cstring>#include <cmath>#include <cstdlib>#include <cstdio>using namespace std;int main(){int N, M;cin>>N>>M;int r = 0;while(M > N){if(M & 1) M++,r++;M /= 2;r++;}cout<<r + N – M<<endl;return 0;}C题#include <iostream>#include <cstring>#include <cstdlib>#include <cstdio>#include <algorithm>#include <cmath>#include <vector>#include <queue>#include <cmath>#define LL long longusing namespace std;const int mod = 1e9 + 7;const int MAXN = 100000 + 10;int C[MAXN];LL pow_mod(LL a, LL b){LL res = 1;while(b){if(b & 1) res = res * a % mod;a = a * a % mod;b>>=1;}return res;}int main(){int n; string s;while(cin>>n){cin>>s;memset(C, 0, sizeof(C));int len = s.length();for(int i=0;i<len;i++){if(s[i] == 'A') C[0]++;else if(s[i] == 'G') C[1]++;else if(s[i] == 'C') C[2]++;else C[3]++;}sort(C,C+4,greater<int>());int x = 1;for(int i=1;i<=3;i++){if(C[i] == C[0]) x++;else break;}int ans = pow_mod(x, n);cout<<ans<<endl;}return 0;}
，最可怕的敌人，就是没有坚强的信念。
