1619: [Usaco2008 Nov]Guarding the Farm 保卫牧场

#include<algorithm>#include<iostream>#include<cstring>#include<cstdio>#define inf 0x7fffffffusing namespace std;inline int read(){    int x=0,f=1;char ch=getchar();    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}    return x*f;}struct data{int x,y,v;}a[1000001];int dx[8] = {-1, -1, 0, 1, 1, 1, 0, -1}, dy[8] = {0, 1, 1, 1, 0, -1, -1, -1} ;  int n,m,ans,mp[1001][1001];bool mark[1001][1001];void dfs(int x,int y){mark[x][y]=1;for(int i=0;i<8;i++){int nowx=x+dx[i],nowy=y+dy[i];if(nowx>=1&&nowy>=1&&nowx<=n&&nowy<=m&&!mark[nowx][nowy]&&mp[nowx][nowy]<=mp[x][y])dfs(nowx,nowy);}}inline bool cmp(data a,data b){return a.v>b.v;}int main(){n=read();m=read();for(int i=1;i<=n;i++)for(int j=1;j<=m;j++){mp[i][j]=read();a[(i-1)*m+j]=(data){i,j,mp[i][j]};}sort(a+1,a+n*m+1,cmp);for(int i=1;i<=n*m;i++)if(!mark[a[i].x][a[i].y])ans++,dfs(a[i].x,a[i].y);printf("%d",ans);return 0;}