第一周题解

栈

20.有效的括号

#include <stdio.h>
#include <string.h>	
char ch1[200], ch2[200];
int answer1();
int answer2();

void main()
{
	gets(ch1);
	
	int i =answer1();
	if(i == 0)		printf("answer1 = Fruse\n");
	else	printf("answer1 = True\n");
	
	int j = answer2();	
	if(j == 0)	printf("answer2 = Fruse");
	else	printf("answer1 = True");
}

int answer1()
{
	int i, answer = 0, n=0;
	char j;
	for(i = 0; i < strlen(ch1); i ++){
		j = ch1[i];
		if(j == '(' || j == '[' || j == '{'){
			ch2[i] = ch1[i];
		}
		else{
			if(j == ')'){
				if(ch2[n] =='('){
					answer = 1;
					n ++;
				}		 
			}
			else if(j == ']'){
				if(ch2[n] =='['){
					answer = 1;
					n ++;
				}		 
			}
			else if(j == '}'){
				if(ch2[n] =='{'){
					answer = 1;
					n ++;
				}		 
			}
		}
	}
	if(answer == 0)		return 0;
	else	return 1;
}

int answer2()
{
	int count = 0, length = strlen(ch1);
	for(int i = 0; i < length; i ++){
		if(ch1[i]=='(' || ch1[i]=='[' || ch1[i]=='{'){
			ch2[count] = ch1[i];
			count ++; //前括号的个数 
		}
		if(ch1[i]==')' || ch1[i]==']' || ch1[i]=='}'){
			if(count-1>=0 && ch2[count-1]-ch1[i]<0 && ch2[count-1]-ch1[i]>=-2) //ASCII表中，左括号与右括号相差1或2 
				count --;
			else	return 0;
		}
	}
	if(count == 0)	return 1;
	else	return 0;
}

42.接雨水

#include<stdio.h>
void answer1(int height[], int length);
void answer2(int height[], int length);

int main()
{
	int length, i, j;
	scanf("%d", &length);
	int height[length];
	for(i = 0; i < length; i ++)
		scanf("%d", &height[i]);
		
	answer1(height, length);	
	answer2(height, length);
}
void answer1(int height[], int length)
{
	int i, j, sum=0;  //总积水量
	int max; //最高的墙的高度 
	for(i = 0; i < length; i ++){
		if(max < height[i])		max = height[i]; 
	}
	for(i = 1; i <= max; i ++){
		int t = 0;
		for(j = 0; j < length-1; j ++){
			if(t && height[j]<i)	sum ++;
			if(height[j] >= i)	t = 1;
		}
	} 
	printf("answer1 = %d\n", sum);
}

void answer2(int height[], int length)
{
	int i, j, sum = 0;
	for(i = 1; i < length; i ++){
		int left = 0;
		for(j = i-1; j >= 0; j --){
			if(height[j] > left)	left = height[j];	
		}
		int right = 0;
		for(j = i+1; j < length; j ++){
			if(height[j] > right)	right = height[j];
		}
		int min = left < right ? left : right;
		if(min > height[i])		sum = sum + (min-height[i]);
	}
	printf("answer2 = %d\n", sum);
}