深度和广度优先算法
全排列的深度优先算法:
#include <iostream>
using namespace std;
int a[10],book[10],n;
void dfs(int step)
{
int i;
if(step==n+1)
{
for(i=1;i<=n;i++)
cout<<a[i];
cout<<endl;
return;
}
for(i=1;i<=n;i++)
{
if(book[i]==0)
{
a[step]=i;
book[i]=1;
dfs(step+1);
book[i]=0;
}
}
return;
}
int main()
{
cin>>n;
dfs(1);
system("pause");
return 0;
}
123+456=789的问题深度优先算法:
#include <iostream>
using namespace std;
int a[10],book[10],total=0;;
void dfs(int step)
{
int i;
if(step==10)
{
if(a[1]*100+a[2]*10+a[3]+a[4]*100+a[5]*10+a[6]==a[7]*100+a[8]*10+a[9])
{
total++;
cout<<a[1]<<a[2]<<a[3]<<"+"<<a[4]<<a[5]<<a[6]<<"="<<a[7]<<a[8]<<a[9]<<endl;
}
return;
}
for(i=1;i<=9;i++)
{
if(book[i]==0)
{
a[step]=i;
book[i]=1;
dfs(step+1);
book[i]=0;
}
}
return;
}
int main()
{
dfs(1);
cout<<total/2<<endl;
system("pause");
return 0;
}
迷宫问题的深度优先算法:
#include <iostream>
using namespace std;
int n,m,p,q, mini=99999999;
int a[51][51], book[51][51];
void dfs(int x,int y, int step)
{
int next[4][2]={{0,1},{1,0},{0,-1},{-1,0}};
int tx,ty,k;
if(x==p&&y==q)
{
if(step<mini)
mini=step;
return;
}
for(k=0;k<=3;k++)
{
tx=x+next[k][0];
ty=y+next[k][1];
if(tx<1||tx>n||ty<1||ty>m)
continue;
if(a[tx][ty]==0&&book[tx][ty]==0)
{
book[tx][ty]=1;
dfs(tx,ty,step+1);
book[tx][ty]=0;
}
}
return;
}
int main()
{
FILE *stream;
freopen_s(&stream,"sample_input.txt", "r", stdin);
int i,j,startx,starty;
cin>>n>>m;
for(i=1;i<=n;i++)
for(j=1;j<=m;j++)
cin>>a[i][j];
cin>>startx>>starty>>p>>q;
book[startx][starty]=1;
dfs(startx,starty,0);
cout<<mini;
fclose(stdin);
system("pause");
return 0;
}
迷宫问题的广度优先算法:
#include <iostream>
using namespace std;
struct node
{
int x;
int y;
int f; //f父亲在队列中的编号, 输出路径用
int step;
};
int main()
{
struct node que[2501];
int a[51][51]={0};
int book[51][51]={0};
int next[4][2]={{0,1},{1,0},{0,-1},{-1,0}};
int head,tail;
int i,j,k,n,m,startx,starty,p,q,tx,ty,flag;
cout<<"Please input the bianjie:";
cin>>n>>m;
cout<<"Please input the array:";
for(i=1;i<=n;i++)
for(j=1;j<=m;j++)
cin>>a[i][j];
cout<<"please input the startx, starty, p,q:";
cin>>startx>>starty>>p>>q;
//队列初始化
head=1;
tail=1;
//往队列插入迷宫入口坐标
que[tail].x=startx;
que[tail].y=starty;
que[tail].f=0;
que[tail].step=0;
tail++;
book[startx][starty]=1;
flag=0;
while(head<tail)
{
for(k=0;k<=3;k++)
{
tx=que[head].x+next[k][0];
ty=que[head].y+next[k][1];
if(tx<1||tx>n||ty<1||ty>m)
continue;
if(a[tx][ty]==0&&book[tx][ty]==0)
{
book[tx][ty]=1;
que[tail].x=tx;
que[tail].y=ty;
que[tail].f=head;
que[tail].step=que[head].step+1;
tail++;
}
if(tx==p&&ty==q)
{
flag=1;
break;
}
}
if(flag==1)
break;
head++;
}
cout<<que[tail-1].step<<endl;
system("pause");
return 0;
}
海岛问题深度优先算法:
#include <iostream>
using namespace std;
int a[51][51], book[51][51],n,m,sum;
void dfs(int x,int y)
{
int k, tx,ty, next[4][2]={{0,1},{1,0},{0,-1},{-1,0}};
for(k=0;k<=3;k++)
{
tx=x+next[k][0];
ty=y+next[k][1];
if(tx<1||tx>n||ty<1||ty>m)
continue;
if(a[tx][ty]>0&&book[tx][ty]==0)
{
sum++;
book[tx][ty]=1;
dfs(tx,ty);
}
}
return;
}
int main()
{
FILE *stream;
freopen_s(&stream,"sample_input.txt", "r", stdin);
//freopen_s(&stream,"sample_output.txt", "w", stdout);
int i,j,startx,starty;
cin>>n>>m>>startx>>starty;
for(i=1;i<=n;i++)
for(j=1;j<=m;j++)
cin>>a[i][j];
book[startx][starty]=1;
sum=1;
dfs(startx,starty);
cout<<sum<<endl;
fclose(stdin);
//fclose(stdout);
system("pause");
return 0;
}
海岛广度优先算法:
#include <iostream>
using namespace std;
struct node
{
int x;
int y;
};
int main()
{
struct node que[2501];
int a[51][51]={0};
int book[51][51]={0};
int next[4][2]={{0,1},{1,0},{0,-1},{-1,0}};
int head,tail;
int i,j,k,n,m,startx,starty,p,q,tx,ty,sum,max=0;
cout<<"Please input n,m,startx, starty:";
cin>>n>>m>>startx>>starty;
cout<<"Please input the array:";
for(i=1;i<=n;i++)
for(j=1;j<=m;j++)
cin>>a[i][j];
//队列初始化
head=1;
tail=1;
//往队列插入降落起始坐标
que[tail].x=startx;
que[tail].y=starty;
tail++;
book[startx][starty]=1;
sum=1;
while(head<tail)
{
for(k=0;k<=3;k++)
{
tx=que[head].x+next[k][0];
ty=que[head].y+next[k][1];
if(tx<1||tx>n||ty<1||ty>m)
continue;
if(a[tx][ty]>0&&book[tx][ty]==0)
{
sum++;
book[tx][ty]=1;
que[tail].x=tx;
que[tail].y=ty;
tail++;
}
}
head++;
}
cout<<sum<<endl;
system("pause");
return 0;
}
判断有几个连续岛屿:
#include <iostream>
#include <iomanip>
using namespace std;
int a[51][51], book[51][51],n,m,sum,area=0;
void dfs(int x,int y,int color)
{
int k, tx,ty, next[4][2]={{0,1},{1,0},{0,-1},{-1,0}};
a[x][y]=color;
for(k=0;k<=3;k++)
{
tx=x+next[k][0];
ty=y+next[k][1];
if(tx<1||tx>n||ty<1||ty>m)
continue;
if(a[tx][ty]>0&&book[tx][ty]==0)
{
sum++;
book[tx][ty]=1;
dfs(tx,ty,color);
book[tx][ty]=0;
}
}
return;
}
int main()
{
FILE *stream;
freopen_s(&stream,"sample_input.txt", "r", stdin);
freopen_s(&stream,"sample_output.txt", "w", stdout);
int i,j,num=0;
cin>>n>>m;
for(i=1;i<=n;i++)
for(j=1;j<=m;j++)
cin>>a[i][j];
for(i=1;i<=n;i++)
{
for(j=1;j<=m;j++)
{
if(a[i][j]>0)
{
sum=1;
num--;
book[i][j]=1;
dfs(i,j,num);
cout<<"每个岛屿的面积为:"<<sum<<endl;
area+=sum;
}
}
}
for(i=1;i<=n;i++)
{
for(j=1;j<=m;j++)
{
cout<<setw(3)<<a[i][j]<<" ";
}
cout<<endl;
}
cout<<"有"<<-num<<"个小岛"<<endl;
cout<<"总面积为"<<area<<endl;
fclose(stdin);
fclose(stdout);
//fclose(stdout);
system("pause");
return 0;
}
炸弹人深度优先:
#include <iostream>
using namespace std;
char a[20][20];
int book[20][20], maxi, mx, my, n, m;
int getnum(int i, int j){
int x, y, sum=0;
x = i; y = j;
while(a[x][y] != '#')
{
if(a[x][y] == 'G')
sum++;
x--;
}
x = i; y = j;
while(a[x][y] != '#')
{
if(a[x][y] == 'G')
sum++;
x++;
}
x = i; y = j;
while(a[x][y] != '#')
{
if(a[x][y] == 'G')
sum++;
y--;
}
x = i; y = j;
while(a[x][y] != '#')
{
if(a[x][y] == 'G')
sum++;
y++;
}
return sum;
}
void dfs(int x, int y)
{
int next[4][2] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
int k, sum, tx, ty;
sum = getnum(x, y);
if(sum > maxi)
{
maxi = sum;
mx = x;
my = y;
}
for(k=0; k<4; k++)
{
tx = x + next[k][0];
ty = y + next[k][1];
//判断边界
if(tx<0 || tx > n-1 || ty < 0 || ty > n-1) continue;
//判断墙和是否走过
if(a[tx][ty] != '.' || book[tx][ty] != 0) continue;
book[tx][ty] = 1;
dfs(tx, ty);
}
return;
}
int main(){
FILE *stream;
freopen_s(&stream,"sample_input.txt", "r", stdin);
int i, startx, starty;
cin>>n>>m>>startx>>starty;
for(i=0; i<n; i++)
{
cin>>a[i];
}
book[startx][starty] = 1;
maxi = getnum(startx, starty);
mx = startx;
my = starty;
dfs(startx, starty);
cout<<"将炸弹放置在("<<mx<<","<<my<<")处, 可以消灭"<<maxi<<"个敌人";
fclose(stdin);
system("pause");
return 0;
}
炸弹人广度优先:
#include <iostream>
using namespace std;
struct Note
{
int x;
int y;
};
char a[20][20];
int getnum(int i, int j){
int x, y, sum=0;
x = i; y = j;
while(a[x][y] != '#')
{
if(a[x][y] == 'G')
sum++;
x--;
}
x = i; y = j;
while(a[x][y] != '#')
{
if(a[x][y] == 'G')
sum++;
x++;
}
x = i; y = j;
while(a[x][y] != '#')
{
if(a[x][y] == 'G')
sum++;
y--;
}
x = i; y = j;
while(a[x][y] != '#')
{
if(a[x][y] == 'G')
sum++;
y++;
}
return sum;
}
int main()
{
FILE *stream;
freopen_s(&stream,"sample_input.txt", "r", stdin);
struct Note que[401];
int head=1, tail=1;
int book[20][20] = {0};
int i, k, tx, ty, startx, starty, sum, max=0, mx, my, m, n;
int next[4][2] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
cin>>n>>m>>startx>>starty;
for(i=0; i<n; i++)
{
cin>>a[i];
}
que[tail].x = startx;
que[tail].y = starty;
tail++;
book[startx][starty] = 1;
max = getnum(startx, starty);
mx = startx; my = starty;
while(head < tail)
{
for(k = 0; k< 4; k++)
{
tx = que[head].x + next[k][0];
ty = que[head].y + next[k][1];
if(tx<0 || tx>n-1 || ty<0 || ty>n-1)
continue;
if(a[tx][ty]=='.'&&book[tx][ty]==0)
{
book[tx][ty] = 1;
que[tail].x = tx;
que[tail].y = ty;
tail++;
sum = getnum(tx, ty);
if(sum > max)
{
max = sum;
mx = tx;
my = ty;
}
}
}
head++;
}
cout<<"将炸弹放置在("<<mx<<","<<my<<")处, 可以消灭"<<max<<"个敌人";
fclose(stdin);
system("pause");
return 0;
}
