1 #include <bits/stdc++.h>
 2 #define fst first
 3 #define scd second
 4 using namespace std;
 5
 6 typedef pair <int,int> P;
 7 const int maxn=700+5;
 8 struct node{
 9     int x,y,d;
10     node(){}
11     node(int x,int y,int d):x(x),y(y),d(d){}
12     bool operator < (const node &a) const { return d>a.d; }
13 }a[maxn*maxn];
14 int n,m;
15 int go[][2]={-1,-1,-1,0,-1,1,0,-1,0,1,1,-1,1,0,1,1};
16 int Map[maxn][maxn];
17 bool vis[maxn][maxn];
18 P q[maxn*maxn];
19
20 inline int read(int &x){ x=0;int k=1;char c;for(c=getchar();c<'0'||c>'9';c=getchar())if(c=='-')k=-1;for(;c>='0'&&c<='9';c=getchar())x=x*10+c-'0';return x*=k; }
21 inline void solve(){
22     int ans=0;
23     for(int i=1;i<=n*m;i++){
24         if(vis[a[i].x][a[i].y]) continue;
25         ans++;
26         int l,r;
27         q[l=r=1]=P(a[i].x,a[i].y);
28         while(l<=r){
29             P u=q[l++];
30             for(int j=0;j<8;j++){
31                 int dx=u.fst+go[j][0],dy=u.scd+go[j][1];
32                 if(Map[u.fst][u.scd]>=Map[dx][dy]&&!vis[dx][dy]){
33                     vis[dx][dy]=true;
34                     q[++r]=P(dx,dy);
35                 }
36             }
37         }
38     }
39     printf("%d\n",ans);
40 }
41 inline void init(){
42     read(n); read(m);
43     for(int i=1;i<=n;i++)for(int j=1;j<=m;j++) read(Map[i][j]),a[(i-1)*m+j]=node(i,j,Map[i][j]);
44     sort(a+1,a+1+n*m);
45     for(int i=0;i<=m+1;i++) Map[0][i]=Map[n+1][i]=-1;
46     for(int i=0;i<=n+1;i++) Map[i][0]=Map[i][m+1]=-1;
47 }
48 int main(){
49     init();
50     solve();
51     return 0;
52 }

View Code

The farm has many hills upon which Farmer John would like to place guards to ensure the safety of his valuable milk-cows. He wonders how many guards he will need if he wishes to put one on top of each hill. He has a map supplied as a matrix of integers; the matrix has N (1 < N <= 700) rows and M (1 < M <= 700) columns. Each member of the matrix is an altitude H_ij (0 <= H_ij <= 10,000). Help him determine the number of hilltops on the map. A hilltop is one or more adjacent matrix elements of the same value surrounded exclusively by either the edge of the map or elements with a lower (smaller) altitude. Two different elements are adjacent if the magnitude of difference in their X coordinates is no greater than 1 and the magnitude of differences in their Y coordinates is also no greater than 1.

农夫JOHN的农夫上有很多小山丘，他想要在那里布置一些保镖（……）去保卫他 的那些相当值钱的奶牛们。 他想知道如果在一座小山丘上布置一名保镖的话，他总共需要招聘多少名保镖。他现在手头有一个用数字矩阵来表示地形的地图。这个矩阵有N行（1 < N < = 100)和M列( 1 < M < = 70) 。矩阵中的每个元素都有一个值H_ij(0 < = H_ij < =10,000)来表示该地区的海拔高度。请你帮助他统计出地图上到底有多少个小山丘。 小山丘的定义是：若地图中一个元素所邻接的所有元素都比这个元素高度要小（或它邻接的是地图的边界），则该元素和其周围所有按照这样顺序排列的元素的集合 称为一个小山丘。这里邻接的意义是：若一个元素与另一个横坐标纵坐标和它的横纵坐标相差不超过1，则称这两个元素邻接。 问题名称：guard 输入格式： 第一行：两个由空格隔开的整数N和M 第二行到第N+1行：第I+1行描述了地图上的第I行，有M个由空格隔开的整数：H_ij. 输入样例：(guard.in): 8 7 4 3 2 2 1 0 1 3 3 3 2 1 0 1 2 2 2 2 1 0 0 2 1 1 1 1 0 0 1 1 0 0 0 1 0 0 0 0 1 1 1 0 0 1 2 2 1 1 0 0 1 1 1 2 1 0 输出格式: 第一行：小山丘的个数 输出样例：(guard.out): 3 输出样例解释： 地图上有三个小山丘：每个小山丘的山峰位置分别在左上角（高度为4），右上角（高度为1）和底部（高度为2）。

* Line 1: Two space-separated integers: N and M

* Lines 2..N+1: Line i+1 describes row i of the matrix with M space-separated integers: H_ij

* Line 1: A single integer that specifies the number of hilltops

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