C++_学习笔记_地图填色问题

 回溯  /  递归

首先判断传入的颜色是否为最后的颜色’d’，如果是说明至少还得向上回溯一次。

如果一切正常不是’d’的话，那就开始填色。

遍历与之相邻的是否重色，如果重色 则本区域取下一色，直到递归传入’d’为之

如果不重色就从第一个颜色开始试探下一区域。

#include<iostream>
#include<vector>
using namespace std;

struct region {
    int id;
    region* next;
    region* last;
}r1,r2,r3,r4,r5,r6,r7;

int a[7][7] = { {0,1,1,1,1,1,0},{1,0,0,0,0,1,0},{1,0,0,1,1,0,0},{1,0,1,0,1,1,0},{1,0,1,1,0,1,0},{1,1,0,1,1,0,0},{0,0,0,0,0,0,0} };

int fill(region currentRegion,int currentColor,int a[7][7],int* result ) {
    //先判断传入颜色是否是d，如果是的话说明还要向上回溯
    if (currentColor <'d')
    {
        result[currentRegion.id - 1] = ++currentColor;
        //判断是否重色
        bool isrepeat = false;
        int temp;
        for (int i = 0; i < 7; i++) {
            if (a[currentRegion.id - 1][i] == 1) {
                if (currentColor == result[i]) {
                    temp = i;
                    isrepeat = true;
                    break;
                }
            }

        }
        if (isrepeat) {
            //先判断是否需要回溯
            cout << currentRegion.id << "is repeat with" << temp + 1 << "," << currentColor << endl;
            if (currentColor == 'd') {
                int rullbackNumber = result[currentRegion.id - 2] + 1;
                result[currentRegion.id - 1] = 0;
                currentRegion = *currentRegion.last;
                fill(currentRegion, rullbackNumber, a, result);
            }
            else {
                //如果重复，填下一个颜色

                fill(currentRegion, currentColor, a, result);
            }

        }
        else {
            if (currentRegion.next)
                fill(*currentRegion.next, 96, a, result);
            else
                return 0;
        }
    }
    else {
        int rullbackNumber = result[currentRegion.id - 2] + 1;
        result[currentRegion.id - 1] = 0;
        currentRegion = *currentRegion.last;
        fill(currentRegion, rullbackNumber, a, result);
    }
     
}

void dispArr(int* arr, int n)
{
    for (int i = 0; i < n; i++)
    {
        char temp = arr[i];
        cout << "arr" << "[" << i +1<< "]" << " is:" << temp << endl;
    }
}



int main() {
    r1.id = 1;
    r2.id = 2;
    r3.id = 3;
    r4.id = 4;
    r5.id = 5;
    r6.id = 6;
    r7.id = 7;
    r1.last = nullptr;
    r1.next = &r2;
    r2.last = &r1;
    r2.next = &r3;
    r3.last = &r2;
    r3.next = &r4;
    r4.last = &r3;
    r4.next = &r5;
    r5.last = &r4;
    r5.next = &r6;
    r6.last = &r5;
    r6.next = &r7;
    r7.last = &r6;
    r7.next = nullptr;

    int* result = new int[7]{0,0,0,0,0,0,0};

    int x=fill(r1,96,a,result);
    dispArr(result, 7);

    delete result;
}

感谢，https://www.cnblogs.com/walter-xh/p/6192800.html