B
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I have a very simple problem for you. Given two integers A and B, your job is to calculate the Sum of A + B.
Input
The first line of the input contains an integer T(1<=T<=20) which means the number of test cases. Then T lines follow, each line consists of two positive integers, A and B. Notice that the integers are very large, that means you should not process them by using 32-bit integer. You may assume the length of each integer will not exceed 1000.
Output
For each test case, you should output two lines. The first line is “Case #:”, # means the number of the test case. The second line is the an equation “A + B = Sum”, Sum means the result of A + B. Note there are some spaces int the equation. Output a blank line between two test cases.
Sample Input
2
1 2
112233445566778899 998877665544332211
Sample Output
Case 1:
1 + 2 = 3
Case 2:
112233445566778899 + 998877665544332211 = 1111111111111111110
s思路及要点
这是一道很典型的大数运算问题,我们可以利用字符串来模拟竖式运算的方法解决。注意的要点有:1、字符型数组要转化为整形数组,需要在每一位上减去‘0’(即字符型的0)。2、为了方便运算,我们需要将加数与被加数的最低位对齐,所以在将字符数组转化为整形数组时,可以将数组逆序排列,保证最低位对齐。3、注意进位。4、由于运算时数组已被逆置,所以在输出时,需要逆序输出,才能保证结果正确。5、注意输出格式,是一次换行还是两次换行。
#include <iostream>#include <stdio.h>#include <string.h>#include <algorithm>using namespace std;char a[1005], b[1005];int main(){ int t; while(scanf("%d", &t) != EOF){ int kase = 0; while(t--){ scanf("%s%s", a, b); int numa[1005] = {0}, numb[1005] = {0}, numc[1005] = {0}; int len_a = strlen(a), len_b = strlen(b); int ma = max(len_a, len_b); for(int i = len_a - 1; i >= 0; i--) numa[len_a - 1 - i] = a[i] - '0'; for(int j = len_b - 1; j >= 0; j--) numb[len_b - 1 - j] = b[j] - '0'; for(int i = 0; i < ma; i++) numc[i] = numa[i] + numb[i]; for(int i = 0; i < ma; i++){ if(numc[i] >= 10){ if(i == ma - 1)ma++; numc[i] -= 10; numc[i+1]++; } } if(kase)printf("\n"); printf("Case %d:\n%s + %s = ", ++kase, a, b); for(int i = ma - 1; i >= 0; i--) printf("%d", numc[i]); printf("\n"); } } return 0;}