原题链接:https://www.luogu.org/problem/show?pid=1514
搜索+贪心(虽然好多题解都是DP)
这样写只能拿90,鬼知道是什么原因。
参考了一篇题解(原题解也是有误的,一样只能拿90)
思路和洛谷题解上的一个是一样的。。。大家去看那个就行。。
1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4 #include <queue> 5 #include <algorithm> 6 #define maxn 520 7 using namespace std; 8 int n,m,ans,i,j; 9 int cnt; 10 int a[maxn][maxn]; 11 bool exist[maxn][maxn]; 12 bool judge[maxn][maxn]; 13 struct node{ 14 int x; 15 int y; 16 bool operator<(const node &rhs)const{ 17 return x < rhs.x; 18 } 19 }; 20 node s[maxn]; 21 int read(){ 22 int num = 0; 23 char c; 24 bool flag = false; 25 while ((c = getchar()) == ' ' || c == ' ' || c == ' '); 26 if (c == '-') 27 flag = true; 28 else 29 num = c - '0'; 30 while (isdigit(c = getchar())) 31 num = num * 10 + c - '0'; 32 return (flag ? -1 : 1) * num; 33 } 34 void dfs(int x,int y){ 35 if (exist[x][y]) 36 return; 37 exist[x][y] = true; 38 if (x+1 <= n && a[x][y] > a[x+1][y]) 39 dfs(x+1,y); 40 if (x-1 >= 1 && a[x][y] > a[x-1][y]) 41 dfs(x-1,y); 42 if (y + 1 <= m && a[x][y] > a[x][y+1]) 43 dfs(x,y+1); 44 if (y - 1 >= 1 && a[x][y] > a[x][y-1]) 45 dfs(x,y-1); 46 } 47 48 int main(){ 49 n = read();m = read(); 50 for (i=1;i<=n;i++) 51 for (j=1;j<=m;j++) 52 a[i][j] = read(); 53 for (i=1;i<=m;i++){ 54 memset(exist,0,sizeof(exist)); 55 dfs(1,i); 56 for (j=1;j<=m;j++) 57 judge[i][j] = exist[n][j]; 58 } 59 cnt = m; 60 for (i=1;i<=m;i++) 61 for (j=1;j<=m;j++) 62 if (judge[j][i]){ 63 cnt--; 64 break; 65 } 66 if (cnt > 0){ 67 printf("0 %d",cnt); 68 return 0; 69 } 70 for (i=1;i<=m;i++){ 71 for (j=1;j<=m;j++) 72 if (judge[i][j]) 73 break; 74 s[i].x = j; 75 for (j = s[i].x + 1;j<=m;j++) 76 if (!judge[i][j]) 77 break; 78 s[i].y = j-1; 79 } 80 sort(s+1,s+m+1); 81 int maxv = 0; 82 int tmp = 0; 83 for (i=1;i<=m;i++){ 84 if (s[i].x > m) 85 break; 86 if (s[i].x <= maxv + 1) 87 tmp = max(tmp,s[i].y); 88 else{ 89 maxv = tmp; 90 ans++; 91 tmp = max(s[i].y,tmp); 92 } 93 } 94 if (maxv != m) 95 ans++; 96 printf("1 %d",ans); 97 return 0; 98 }