#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int MAX = 1e6 + 10;
int a[MAX];
int main()
{
int n, m, flag, i, j;
char c;
scanf("%d%d", &n, &m);
flag = 0;
getchar();
for (i = 0; i < n; i++)
{
for (j = 0; j < m; j++)
{
scanf("%c", &c);
getchar();
if (c == 'C' || c == 'M' || c == 'Y')
{
flag = 1;
}
}
}
if (flag == 0)
{
printf("#Black&White\n");
}
else
{
printf("#Color\n");
}
return 0;
}
N - Repeating Cipher
#include<bits/stdc++.h>
using namespace std;
int main()
{
int n;
cin>>n;
string a;
cin>>a;
int i = 0, k=0;
while (a[i] != '\0') // \0 为 空字符（ascii码为0的字符），在C语言中作为字符串结束符使用
{
cout<<a[i];
k++;
i+=k;// 1=0+1 3=1+2 6=1+2+3 10=1+2+3+4
}
return 0;
}
O - Odd Selection
#include<bits/stdc++.h>
using namespace std;
const int N=1e3+5;
int n,m,b,c,a;
int main()
{
int t;
cin >> t;
while(t--)
{
int n,x,a = 0,b = 0,num;
cin>>n>> x;
for(int i=0; i<n; i++)
{
cin>>num;
if(num%2==0)
{
a++;
}
else
b++;
}
if(b == 0||(a == 0 && x % 2 == 0)||(x==n&&b%2==0))
cout << "No" << endl;
else
cout << "Yes" << endl;
}
}