第二周题解

84.柱形图中最大的矩形

#include<stdio.h>
void answer1(int n, int list[]);
void answer2(int n, int list[]);
void answer3(int n, int list[], int left, int right);
int findMin(int left, int right, int list[]);
int Max;

int main()
{
	int n;
	scanf("%d", &n); //几个柱子
	int list[n];
	for(int i = 0; i < n; i ++)
		scanf("%d", &list[i]);
	
	answer1(n, list);
	answer2(n, list);
	answer3(n, list, 0, n-1);
	printf("%d", Max);
}

void answer1(int n, int list[])
{
	int max = 0;
	for(int i = 0; i < n; i ++){
		for(int j = i; j < n; j ++){
			int min = list[i];
			for(int k = i + 1; k <= j; k ++){
				min = list[k] > min ? min : list[k];
			}
			max = min*(j - i + 1) > max ? min*(j - i + 1) : max;
		}
	}
	printf("%d\n", max);
}

void answer2(int n, int list[])
{
	int max = 0;
	for(int i = 0; i < n; i ++){
		int min = 99999; 
		for(int j = i; j < n; j ++){
			min = min < list[j] ? min : list[j];
			max = max > min * (j - i + 1) ? max : min * (j - i + 1);
		}
	}
	printf("%d\n", max);
}

void answer3(int n, int list[], int left, int right)
{
	if(left > right)
		return ;
	int min = findMin(left, right, list);
	int max = (right - left + 1) * list[min];
	if(max > Max)
		Max = max;
	if(left < min && min != 0)
		answer3(n, list, left, min-1);
	if(right > min && min != n)
		answer3(n, list, min+1, right);
}
int findMin(int left, int right, int list[])
{
	int min = left;
	for(int i = left+1; i <= right; i ++){
		if(list[i] < list[min])
			min = i;
	}
	return min;
}

85.最大矩形

#include<stdio.h>
int a, b;  //矩形的长和宽 
void answer1(int matrix[a][b]);

int main()
{
	scanf("%d %d", &a, &b);
	int matrix[a][b];
	for(int i = 0; i < a; i ++){
		for(int j = 0; j < b; j ++)
			scanf("%d", &matrix[i][j]);
	}
	
	answer1(matrix);
}
void answer1(int matrix[a][b])
{
	int book[a][b];
	int max = 0;
	for(int i = 0; i < a; i ++){
		for(int j = 0; j < b; j ++){
			if(matrix[i][j] == 1){
				if(j == 0)
					book[i][j] = 1;
				else
					book[i][j] = book[i][j-1] + 1;
			}
			else
				book[i][j] = 0;
			int min = book[i][j];
			for(int k = i; k >=0; k --){
				int height = i - k + 1;
				if(min > book[k][j])
					min = book[k][j];
				if(max < height*min)
					max = height*min;
			}
		}		
	}
	printf("%d", max);
}