最近做的一些深搜题目

关于一些深搜的题目,有很多是按照
碧海潮升的小屋
里面介绍的一些排列组合算法做的,那里面对递归组合介绍的很好

zoj2412

一个普通的深度优先搜索，我的代码比较啰嗦，嘿嘿，反正多一点不要钱

#include <iostream>
#include <string.h>
using namespace std;
char map[51][51];
char status[51][51];
int n,m;
int ok(int x,int y,char z)
{
        int a,b,c,d;
        a = b = c = d = 0;
        switch(map[x][y])
        {
                case 'A':
                        a=d=1;
                        break;
                case 'B':
                        a=b=1;
                        break;
                case 'C':
                        d=c=1;
                        break;
                case 'D':
                        b=c=1;
                        break;
                case 'E':
                        a=c=1;
                        break;
                case 'F':
                        b=d=1;
                        break;
                case 'G':
                        a=b=d=1;
                        break;
                case 'H':
                        a=c=d=1;
                        break;
                case 'I':
                        b=c=d=1;
                        break;
                case 'J':
                        a=b=c=1;
                        break;
                case 'K':
                        a=b=c=d=1;
                        break;
        }
        if(z=='a'&&a==1) return 1;
        else if(z=='b'&&b==1) return 1;
        else if(z=='c'&&c==1) return 1;
        else if(z=='d'&&d==1) return 1;
        else
                return 0;
}
void chuandfs(int x,int y)
{
        int a,b,c,d;
        a = b = c = d = 0;
        switch(map[x][y])
        {
                case 'A':
                        a=d=1;
                        break;
                case 'B':
                        a=b=1;
                        break;
                case 'C':
                        d=c=1;
                        break;
                case 'D':
                        b=c=1;
                        break;
                case 'E':
                        a=c=1;
                        break;
                case 'F':
                        b=d=1;
                        break;
                case 'G':
                        a=b=d=1;
                        break;
                case 'H':
                        a=c=d=1;
                        break;
                case 'I':
                        b=c=d=1;
                        break;
                case 'J':
                        a=b=c=1;
                        break;
                case 'K':
                        a=b=c=d=1;
                        break;
        }
        if(a==1&&x-1>0&&ok(x-1,y,'c')&&status[x-1][y]==0)
        {
                status[x-1][y] = 1;
                chuandfs(x-1,y);
        }
        if(b==1&&y+1<=m&&ok(x,y+1,'d')&&status[x][y+1]==0)
        {
                status[x][y+1] = 1;
                chuandfs(x,y+1);
        }
        if(c==1&&x+1<=n&&ok(x+1,y,'a')&&status[x+1][y]==0)
        {
                status[x+1][y] = 1;
                chuandfs(x+1,y);
        }
        if(d==1&&y-1>0&&ok(x,y-1,'b')&&status[x][y-1]==0)
        {
                status[x][y-1] = 1;
                chuandfs(x,y-1);
        }
}
int main()
{
        int i,j,cnt;
        bool ff;
        while(cin >> n >> m)
        {
                ff = false;cnt = 0;
                if(n==-1&&m==-1) break;
                for(i=1;i<=n;++i)
                        for(j=1;j<=m;++j)
                                cin >> map[i][j];
                memset(status,0,sizeof(status));
                while(ff==false)
                {
                        ff = true;
                        for(i=1;i<=n;++i)
                                for(j=1;j<=m;++j)
                                {
                                        if(status[i][j]==0)
                                        {
                                                ff = false;
                                                status[i][j] = 1;
                                                chuandfs(i,j);
                                                cnt++;
                                        }
                                }
                }
                cout << cnt << endl;
        }
        return 0;
}

zoj 1694

一个比较有意思的DFS
对 "当前目标是否要划开" 做一个递归
然后对已经出现比目标大的情况剪枝就是可以了
<本题使用STL>

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
vector<int> num;
vector<int> rcd(15);
vector<int> minsum(15);
int pos = 0,mpos;
int len,minval,n;
bool ff;
void chuandfs(int p,int sum,int cur)
{

        if(sum+cur>n)//如果已经比目标数大了,那么剪枝
                return;
        if(p<len)//如果层数少于LEN,则每次分两种情况讨论
        {
                rcd[pos++] = cur*10 + num[p];
                chuandfs(p+1,sum+cur*10+num[p],0);
                rcd[pos--] = 0;
                if(p!=len-1)//如果已经到底了,那么就不用这种情况了
                        chuandfs(p+1,sum,cur*10+num[p]);
        }
        else
        {
                sum += cur;
                if(sum==minval)//当前最接近值已经出现过
                {
                        ff = true;
                }
                if(sum<=n&&sum>minval)//出现新的最接近值
                {
                        minval = sum;
                        ff = false;
                        mpos = pos;
                        for(int x=0;x<pos;++x)//将当前最接近值保存起来
                                minsum[x] = rcd[x];
                        if(cur!=0)//另一种情况
                        {
                                minsum[pos] = cur;
                                mpos++;
                        }
                        /*cout << "key is :" << minval << endl;*/
                }
                return;
        }
}
int main()
{       
        int m,i,t;
        while(cin >> n)
        {
                if(n==0)
                        break;
                cin >> m;
                num.clear();               
                t = 0;               
                if(m==n)
                {
                        cout << n << " " << n << endl;
                        continue;
                }
                while(m>0)
                {
                        num.push_back(m%10);
                        t += m%10;
                        m /= 10;
                }
                if(t>n)
                {
                        cout << "error" << endl;
                        continue;
                }
                len = num.size();
                for(i=0;i<len/2;++i)
                        std::swap(num[i],num[len-i-1]);
                minval = 0;
                ff = false;
                chuandfs(0,0,0);
                if(ff == true)
                {
                        cout << "rejected" << endl;
                        continue;
                }
                if(minval<0) minval*=-1;
                cout << minval;
                for(int x=0;x<mpos;++x)
                {
                        cout << " " << minsum[x];
                }
                cout << endl;
        }
}