1065. A+B and C (64bit) (20)

1.使用string读取a和b，如果符号相同，按照字符串来处理，因为两个负数或者两个正数相加，会超过最大的取值范围

2.如果符号不同，那么a+b一定会在范围内，可以使用long long进行处理和比较

//#include<string>//#include<stack>//#include<unordered_set>//#include <sstream>//#include "func.h"//#include <list>#include <iomanip>#include<unordered_map>#include<set>#include<queue>#include<map>#include<vector>#include <algorithm>#include<stdio.h>#include<iostream>#include<string>#include<memory.h>#include<limits.h>#include<stack>using namespace std;/*10009223372036854775807 -9223372036854775808 09223372036854775807 -9223372036854775806 09223372036854775808 -9223372036854775807 19223372036854775808 -9223372036854775807 21 1 01 1 21 1 3-1 -1 0-1 -1 -2-1 -1 -3*/long long str2long(string a){long long ans = 0;for (int i = 0; i < a.size(); i++)ans = ans * 10 + a[i] - '0';return ans;}string reverseStr(string a){for (int i = 0; i < a.size() / 2; i++)swap(a[i], a[a.size() - 1 - i]);return a;}int main(void){int n;cin >> n;for (int k = 0; k < n;k++){bool isBigger = true;string a, b;cin >> a >> b;bool aPositive = false;bool bPositive = false;//如果是负数，则进行标记和去掉负号if (a[0] == '-'){a = a.substr(1);aPositive = true;}if (b[0] == '-'){b = b.substr(1);bPositive = true;}if ((aPositive&&bPositive) || (!aPositive&&!bPositive)){string ans = "";if (a.size() > b.size()) swap(a, b);//保证a最短a = reverseStr(a);b = reverseStr(b);int i = 0;int carry = 0;for (; i < a.size(); i++){int sum = a[i] - '0' + b[i] - '0' + carry;carry = sum / 10;char c = sum % 10 + '0';ans = c + ans;}for (; i < b.size(); i++){int sum = b[i] - '0' + carry;carry = sum / 10;char c = sum % 10 + '0';ans = c + ans;}if (carry != 0){char c = carry + '0';ans = c + ans;}//输入cstring c;cin >> c;bool cPositive = false;if (c[0] == '-'){c = c.substr(1);cPositive = true;}if (aPositive&&bPositive && cPositive){//a+b为负数，c为负数if (ans.size() > c.size())//a+b的绝对值大于c的绝对值isBigger = false;else if (ans.size() == c.size()){for (int i = 0; i < ans.size(); i++){if (ans[i]>c[i]){//a+b的绝对值大于c的绝对值isBigger = false;break;}else if (ans[i] < c[i]){//a+b的绝对值小于c的绝对值isBigger = true;break;}}if (ans == c) isBigger = false;//相等的话，为false}elseisBigger = true;}else if (aPositive&&bPositive && !cPositive){//a+b为负数，c为正数isBigger = false;}else if (!aPositive&&!bPositive && cPositive){//a+b为正数，c为负数isBigger = true;}else{//a+b为正数，c为正数if (ans.size() > c.size())//a+b的绝对值大于c的绝对值isBigger = true;else if (ans.size() == c.size()){for (int i = 0; i < ans.size(); i++){if (ans[i]>c[i]){//a+b的绝对值大于c的绝对值isBigger = true;break;}else if (ans[i] < c[i]){//a+b的绝对值小于c的绝对值isBigger = false;break;}}if (ans == c) isBigger = false;//相等的话，为false}elseisBigger = false;}}else{long long aInt = str2long(a), bInt = str2long(b);long long ans;if (!aPositive&&bPositive)ans = aInt - bInt;elseans = bInt - aInt;long long c;cin >> c;if (ans > c)isBigger = true;else isBigger = false;}if (isBigger)printf("Case #%d: true\n", k + 1);elseprintf("Case #%d: false\n", k + 1);}return 0;}