题解 | #八皇后#

#include <cstdio>
#include <vector>
#include <string>
#include <cstring>
using namespace std;

vector<string> queen_str;
bool visited[10][10];

void visit(int line,int col){
    for (int i = 0; i < 8; ++i) {
        visited[line][i]= true;
    }
    for (int j = 0; j < 8; ++j) {
        visited[j][col]= true;
    }
    int beg_line_1;
    int beg_col_1;
    if(line+col<8){
        beg_col_1=line+col;
        beg_line_1=0;
    }else{
        beg_line_1=line+col-7;
        beg_col_1=7;
    }
    int idx,jdx;
    for(idx=beg_line_1,jdx=beg_col_1;idx<8,jdx>=0;idx++,jdx--){
        visited[idx][jdx]= true;
    }
    int beg_line_2;
    int beg_col_2;
    if (line>col){
        beg_line_2=line-col;
        beg_col_2=0;
    }else{
        beg_line_2=0;
        beg_col_2=col-line;
    }
    int mdx,kdx;
    for(mdx=beg_line_2,kdx=beg_col_2;mdx<8,kdx<8;mdx++,kdx++){
        visited[mdx][kdx]= true;
    }
}


void DFS(int col,int queen,string str){
    if(queen==8){
        queen_str.push_back(str);
        return;
    }
    for (int line = 0; line < 8; ++line) {
        if(visited[line][col]){
            continue;
        }
        str.push_back(line+1+'0');
        bool visited_old[10][10];
        for (int i = 0; i < 10; ++i) {
            for (int idx = 0; idx < 10; ++idx) {
                visited_old[i][idx]=visited[i][idx];
            }
        }
        visit(line,col);
        DFS(col+1,queen+1,str);
        for (int i = 0; i < 10; ++i) {
            for (int idx = 0; idx < 10; ++idx) {
                visited[i][idx]=visited_old[i][idx];
            }
        }
        str.pop_back();
    }
    return;
}

int main() {
    int n;
    int queen=0;
    memset(visited,false,100);
    DFS(0,0,"");
    while(scanf("%d",&n)!=EOF){
        printf("%s\n",queen_str[n-1].c_str());
    }
}