Binary String Constructing CodeForces - 1003B (构造)

B. Binary String Constructing
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

You are given three integers aabb and xx. Your task is to construct a binary string ss of length n=a+bn=a+b such that there are exactly aa zeroes, exactly bb ones and exactly xx indices ii (where 1i<n1≤i<n) such that sisi+1si≠si+1. It is guaranteed that the answer always exists.

For example, for the string "01010" there are four indices ii such that 1i<n1≤i<n and sisi+1si≠si+1 (i=1,2,3,4i=1,2,3,4). For the string "111001" there are two such indices ii (i=3,5i=3,5).

Recall that binary string is a non-empty sequence of characters where each character is either 0 or 1.

Input

The first line of the input contains three integers aabb and xx (1a,b100,1x<a+b)1≤a,b≤100,1≤x<a+b).

Output

Print only one string ss, where ss is any binary string satisfying conditions described above. It is guaranteed that the answer always exists.

Examples
input
Copy
2 2 1
output
Copy
1100
input
Copy
3 3 3
output
Copy
101100
input
Copy
5 3 6
output
Copy
01010100
Note

All possible answers for the first example:

  • 1100;
  • 0011.

All possible answers for the second example:

  • 110100;
  • 101100;
  • 110010;
  • 100110;
  • 011001;
  • 001101;
  • 010011;

  • 001011.

题意:给出a,b,x,构造一个01串,有a个0,b个1。这个01串刚好有x个 ai 使得ai!=ai+1。


思路:对于x,我们很容易就可以想到先输出x/2对0和1(n对0和1交错出现可以提供2*n-1个符合题意的ai),然后将剩余的0和剩余的1连续输出(提供1个符合条件的ai,这样就刚好是x个符合条件的ai了,需要注意的是,我们要优先将个数多的放在前面,例如,有10个1,5个0的话,我们先输出x/2个“10”,否则,输出x/2个“01”)。


#include "iostream"
using namespace std;
int main()
{
    int a,b,x,n;
    char u,v;
    cin>>a>>b>>x;
    n=a+b;
    if(a>b) u='0',v='1';
    else {u='1',v='0';swap(a,b);}
    for(int i=0;i<x/2;i++) {cout<<u<<v;a--,b--;}
    if(x%2==0){
        while(b--) cout<<v;
        while(a--) cout<<u;
    }
    else{
        while(a--) cout<<u;
        while(b--) cout<<v;
    }
    return 0;
}

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转载自blog.csdn.net/qq_41874469/article/details/80913513
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