15北京区域赛——构造——hihoCoder 1257 Snake Carper

注意是正的偶数。。不包括零

还有n=2的时候应该横着放

#include <cstdio>
#include <algorithm>
using namespace std;
void dfs(int n)
{
    if(n == 1){
        printf("1 1
");
        return;
    }
    else if(n ==2){
        printf("1 1
");
        printf("1 2 1 3
");
        return;
    }
    else if(n == 3){
        printf("1 2
");
        printf("1 1 2 1
");
        printf("1 3 2 3 2 2
");
        return;
    }
    else if(n % 2 == 1){
        dfs(n-3);
        int num = (n-3)*(n-2)/2;
        int col = (n-2)/2;
        int row = num/col;
        //n-2
        for(int i = 1; i <= col; i++)
            printf("%d %d ", i, row+1);
        printf("%d %d ", col+1, row+1);
        for(int i = 1; i <= col; i++){
            printf("%d %d ", col+1, row-i+1);
        }
        puts("");
        //n-1
        for(int i = 1; i <= (n-1)/2; i++)
            printf("%d %d ", col+1, i);
        for(int i = (n-1)/2; i >= 1; i--)
            printf("%d %d ", col+2, i);
        puts("");
       //n
       for(int i = 1; i <= n/2; i++)
          printf("%d %d ", col+2, (n-1)/2+i);
        printf("%d %d ", col+2, row+2);
       for(int i = 1; i <= n/2; i++)
          printf("%d %d ", col+2-i, row+2);
       puts("");
    }
    else {
       dfs(n-1);
       int num = (n-1)*n/2;
       int col = n/2;
       int row = num/col;
       for(int i = 1; i <= n/2; i++)
          printf("%d %d ", i, row+1);
       for(int i = n/2; i >= 1; i--)
           printf("%d %d ", i, row+2);
       puts("");
    }
}
int main()
{
    int n;
    while(~scanf("%d", &n)){
        int xx, yy;
        if(n % 2 == 1){
             xx = (n+1)/2;
             yy = n;
        }
        else {
             xx = n/2;
             yy = n+1;
        }
        printf("%d %d
", xx, yy);
    dfs(n);
    }
    return 0;
}