CSP初赛复习-27-搜索与回溯-练习题

CSP初赛复习-27-搜索与回溯-练习题

PDF及答案公众号回复关键字:CSPC27

阅读程序

#include <iostream>
using namespace std;
int n,i,j,a[100][100];
int solve(int x,int y)
{
	int u,v;
	if(x==n) return a[x][y];
	u=solve(x+1,y);
	v=solve(x+1,y+1);
	if(u>v) return a[x][y]+u;
	else return a[x][y]+v;	
}
int main()
{
	cin>>n;
	for(i=1;i<=n;i++)
		for(j=1;j<=i;j++) cin>>a[i][j];
	cout<<solve(1,1)<<endl;
	return 0;	
}
/*
输入
5   
2   
-1 4   
2 -1 -2   
-1 6 4 0   
3 2 -1 5 8  
输出:
?
*/

2

#include <stdio.h> 
#include <string.h> 
#define SIZE 100 
int n, m, p, count; 
int a[SIZE][SIZE]; 
void colour(int x, int y) 
{ 
	count++; 
	a[x][y] = 1; 
	if ((x > 1) && (a[x - 1][y] == 0)) 
		colour(x - 1, y); 
	if ((y > 1) && (a[x][y - 1] == 0)) 
		colour(x, y - 1); 
	if ((x < n) && (a[x + 1][y] == 0)) 
		colour(x + 1, y); 
	if ((y < m) && (a[x][y + 1] == 0)) 
		colour(x, y + 1);  
} 
int main() 
{ 
	int i, j, x, y, ans; 
	memset(a, 0, sizeof(a)); 
	scanf("%d%d%d", &n, &m, &p); 
	for (i = 1; i <= p; i++) { 
		scanf("%d%d", &x, &y); 
		a[x][y] = 1; 
	} 
	ans = 0;
	for (i = 1; i <= n; i++) 
		for (j = 1; j <= m; j++) 
			if (a[i][j] == 0) { 
				count = 0; 
				colour(i, j); 
				if (ans < count) 
					ans = count; 
			} 
	printf("%d\n", ans); 
	return 0; 
} 
/*
输入:
6 5 9
1 4
2 3
2 4
3 2
4 1
4 3
4 5
5 4
6 4
输出:
?
*/