uva-321-暴力枚舉-隱式圖搜尋

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題意：給你n個房間,有許多燈的控制開關,i房間燈的開關在j房間,未開燈的房間不能進,i房間和j房間之間如果沒有門,也不能從i進入到j,開始房間是1，並且燈是開著的,問你是否能夠走到最後一個房間n,並且此時其他房間的燈都是關著的.如果存在多個解,輸出操作步數最小的操作序列.

範圍：n<=10,

解題思路:設狀態為,當前的房間編號+當前其他房間燈的狀態.所以總的狀態為N*2^N,最大值10*1024，裸枚舉.

注意，這道題目每次枚舉都必須從房間編碼1-N,要不然會wa，而且,PE也wa.使用了位標誌房間燈的狀態.

#include <iostream>#include<map>#include<memory.h>#include<stdio.h>#include<string>#include<queue>#include<vector>using namespace std;const int  MAXN = 11;class Node{public:    vector<string>step;    int cur;    int curStepNum;    int lights;    Node()    {        //step.reserve(65535);    }    bool operator <(const Node& node) const    {        return curStepNum > node.curStepNum;    };};int conn[MAXN][MAXN];int contro[MAXN][MAXN];int r, d, s;int states[10][1025];priority_queue<Node>q;int perLights[10] = {    1 << 0,1 << 1,1 << 2 ,1 << 3 ,1 << 4 ,1 << 5 ,    1 << 6,1 << 7,1 << 8 ,1 << 9 };void read(){    int ss, ee;    for (int i = 0;i < d;i++)    {        cin >> ss >> ee;        //start with 0        conn[ss - 1][ee - 1] = 1;        conn[ee - 1][ss - 1] = 1;    }    for (int i = 0;i < s;i++)    {        cin >> ss >> ee;        contro[ss - 1][ee - 1] = 1;    }}Node bfs(){    Node node;    node.cur = 0;    node.curStepNum = 0;    node.lights = 1;    q.push(node);    //init node 只有0房間是亮的    states[0][1] = 1;    while (q.empty() == false)    {        node = q.top();        q.pop();        int curIndex = node.cur;        //cur lights state        int curLights = node.lights;        int curStepNum = node.curStepNum;        //判斷是不是終點        if ((curIndex == r - 1) && curLights == perLights[r - 1])        {            return node;        }            //枚舉燈的狀態        for (int i = 0;i < 10; i++)        {            if (contro[curIndex][i] == 0)                continue;            if (i == curIndex)                continue;            //控制的燈            int nextControLightIndex = i;            string desc = "";            int nextLight = 0;            if ((curLights & perLights[nextControLightIndex]) == perLights[nextControLightIndex])            {                //關閉next房間的燈                nextLight = (curLights ^ perLights[nextControLightIndex]);                if (states[curIndex][nextLight] == 1)                    //repeat                    continue;                desc = "- Switch off light in room " + std::to_string(nextControLightIndex + 1);                desc += ".";            }            else            {                //開啟next房間的燈                nextLight = curLights | perLights[nextControLightIndex];                if (states[curIndex][nextLight] == 1)                    //repeat                    continue;                desc = "- Switch on light in room " + std::to_string(nextControLightIndex + 1);                desc += ".";            }            Node newNode;            newNode.curStepNum = curStepNum + 1;            newNode.cur = curIndex;            newNode.lights = nextLight;            newNode.step = node.step;            newNode.step.push_back(desc);            //push to queue            q.push(newNode);            states[curIndex][nextLight] = 1;        }        //end curIndex enum lights state        //start door        for (int i = 0;i < 10;i++)        {            if (curIndex == i)                continue;            if (conn[curIndex][i] == 0)                continue;            int nextDoor = i;            if ((perLights[nextDoor] & curLights) == 0)                //燈是滅的,不能進                continue;            if (states[nextDoor][curLights] == 1)                //已經看到過,不能進                continue;            //燈是開著的,能進            Node newNode;            newNode.cur = nextDoor;            newNode.curStepNum = curStepNum + 1;            newNode.lights = curLights;            newNode.step = node.step;            string desc = "- Move to room " + std::to_string(nextDoor + 1);            desc += ".";            newNode.step.push_back(desc);            states[nextDoor][curLights] = 1;            q.push(newNode);        }    }    node.cur = -1;    return node;}int main(){    int t = 0;    while (cin >> r >> d >> s)    {        if (r == d && d == s && r == 0)            break;        memset(conn, 0, sizeof(conn));        memset(contro, 0, sizeof(conn));        memset(states, 0, sizeof(states));        while (q.empty() == false)            q.pop();        read();                cout << "Villa #";        cout << t + 1 << endl;        if (r == 1)        {            cout << "The problem can be solved in " << 0 << " steps:" << endl;        }        else        {            Node node = bfs();            //cout << "test" << endl;            if (node.cur == -1)            {                cout << "The problem cannot be solved." << endl;            }            else            {                cout << "The problem can be solved in " << node.curStepNum << " steps:" << endl;                vector<string> b = node.step;                for (int i = 0;i <= b.size() - 1;i++)                    cout << b[i] << endl;;            }        }        t++;        cout << endl;    }}

 

uva-321-暴力枚舉-隱式圖搜尋