POJ 2386 Lake Counting

来源：互联网发布：win8.1无法连接windows 编辑：程序博客网时间：2024/06/14 09:43

这个感觉用不到动态规划

自己一次就想出来了

做完后看了看网上大神的解法，发现直接用深度遍历更快。

先给出自己404k 94ms的代码，在粘上大神192k 0ms的代码

代码：

#include <iostream>#include <string>using namespace std;struct element{bool water;int row;int col;int id;};void update_pondid(int row, int col, element ** arr,int arrrow, int arrcol,int oldid,int newid){int i;int j;for (  i = 0; i <= row; i++ ){for ( j = 0; j < arrcol; j++ ){if(arr[i][j].id == oldid )arr[i][j].id = newid;}}}void Around_Judge(int row, int col, element ** arr,int arrrow, int arrcol,int *pondcount,int * ponddelete){if(arr[row][col].water){int l = -1, rt = -1;int id = -1;bool re = false;if( (col - 1) >= 0 && arr[row][col-1].water ){id = l = arr[row][col-1].id;re = true;}if( (col - 1) >= 0 && (row - 1) >= 0 && arr[row-1][col-1].water ){id = arr[row-1][col-1].id;re = true;}if( (row - 1) >= 0 && arr[row-1][col].water ){id = arr[row-1][col].id;re = true;}if( (col + 1) < arrcol && (row - 1) >= 0 && arr[row-1][col+1].water){rt = arr[row-1][col+1].id;re = true;}if(!re){*pondcount +=1;arr[row][col].id = *pondcount;}else if( id != -1 && rt != -1 && id != rt ){arr[row][col].id = id;update_pondid(row, col, arr,arrrow,arrcol,rt,id);*ponddelete +=1;}else{id > rt ? arr[row][col].id = id: arr[row][col].id = rt;}}}int main(){int r = 0 , c = 0 ;cin>>r>>c;element **arr = new element*[r];for(int i = 0; i < r; i++ )arr[i] = new element[c];//初始化int i;int j;for (  i = 0; i < r; i++ ){for ( j = 0; j < c; j++ ){char t;cin>>t;element ele = {false,i,j,0};if( t == 'W' )ele.water = true;arr[i][j] = ele;}}int * count = new int;*count = 1;int * dele = new int;*dele = 1;for (  i = 0; i < r; i++ ){for ( j = 0; j < c; j++ ){Around_Judge(i,j,arr,r,c,count,dele);}}cout<<(*count) - (*dele) <<endl;return 0;}

大神的代码：

#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>#include <queue>using namespace std;#define maxn 106struct XPoint{    int x;    int y;    XPoint(int xx, int yy) :        x(xx), y(yy)    {    }    XPoint()    {    }};int n, m;bool map[maxn][maxn];bool vis[maxn][maxn];int ans;int dir[8][2] ={{ -1, -1 },{ -1, 0 },{ -1, 1 },{ 0, -1 },{ 0, 1 },{ 1, -1 },{ 1, 0 },{ 1, 1 } };bool ok(int x, int y){    if (x < 0 || y < 0 || x >= n || y >= m)        return false;    if (vis[x][y])        return false;    return map[x][y];}void work(int x, int y){    ans++;    queue<XPoint> q;    q.push(XPoint(x, y));    vis[x][y] = true;    while (!q.empty())    {        XPoint temp = q.front();        q.pop();        for (int i = 0; i < 8; i++)            if (ok(temp.x + dir[i][0], temp.y + dir[i][1]))            {                vis[temp.x + dir[i][0]][temp.y + dir[i][1]] = true;                q.push(XPoint(temp.x + dir[i][0], temp.y + dir[i][1]));            }    }}int main(){    //freopen("t.txt", "r", stdin);    scanf("%d%d", &n, &m);    memset(map, 0, sizeof(map));    memset(vis, 0, sizeof(vis));    ans = 0;    getchar();    for (int i = 0; i < n; i++)    {        for (int j = 0; j < m; j++)        {            char ch;            scanf("%c", &ch);            if (ch == 'W')                map[i][j] = true;        }        getchar();    }    for (int i = 0; i < n; i++)        for (int j = 0; j < m; j++)            if (!vis[i][j] && map[i][j])                work(i, j);    printf("%d\n", ans);    return 0;}

0 0