POJ 1504

题意

把两个数字翻转之后相加，再翻转回来的到结果

思路

翻转之后再翻转回来，所以可以视为不用翻转，从左向右加，进位向右进位。

#include <iostream>
#include <cstring>
#include <cstdio>
#include <cstdlib>
using namespace std;

int n1,n2;
int a[100],b[100];
void add(){
    for(int i=0;i<(n1>n2?n1:n2);i++){
        a[i] = a[i] + b[i];
        if(a[i]>9){
            a[i] -= 10;
            a[i+1]++;
        }
    }
}
int main(){
    int t;
    char s1[100],s2[100];
    scanf("%d",&t);
    while(t--){
        scanf("%s%s",s1,s2);
        memset(a,0,sizeof(a));
        memset(b,0,sizeof(b));
        n1 = strlen(s1);
        n2 = strlen(s2);
        for(int i = 0;i<n1;i++){
            a[i] = s1[i] - '0';
        }
        for(int i =0;i<n2;i++){
            b[i] = s2[i]-'0';
        }
        add();

        int right = 0;
        while(1){
            if(a[right] == 0)
                right++;
            else
                break;
        }
        int left = n1 + n2;
        while(1){
            if(a[left]==0)
                left--;
            else
                break;
        }
        for(int i = right;i<=left;i++){
            printf("%d",a[i]);
        }
        printf("\n");
    }
}