XDOJ 730 一元稀疏多项式的简单计算器 (Copilot 辅助代码)

标题  

一元稀疏多项式计算器

时间限制

2S

内存限制

10000 Kb

问题描述

设计一个一元稀疏多项式的简单计算器，要求能进行加减运算。

问题输入

每组数据有3行构成，第1行为3个正整数n，m，t， n表示第一个多项式的项数，m表示第二个多项式的项数，t表示运算类型，0为加法，1为减法，每组数据的第2行包含2n个整数，每两个整数分别表示第一个多项式每一项的系数和指数；第3行包含2m个整数，每两个整数分别表示第二个多项式每一项的系数和指数。输入每一项按指数从低到高的顺序排列。

问题输出

在一行上以多项式形式输出结果，指数按从低到高的顺序

输入样例

6 3 0

1 0 1 1 -3 2 1 3 1 4 1 5

-1 3 -2 4 1 5

输出样例

1+x-3x^2-x^4+2x^5

1.本题是 Felix 第一次用 vscode 自动代码补全写的代码，可以说 Copilot 真的很好用，定义一个变量， if 一下， 所有代码都提示出来了；

2.80 分的原因可能是没有考虑最终相减为 0 的情况

3.注意迭代器不能在遍历时 erase 删除

// 2024/12/30 OK with the help of Copilot
#include <bits/stdc++.h>

using namespace std;

int n, m, t;
map<int, int> mp1, mp2;

map<int, int> Addition(map<int, int> mp1, map<int, int> mp2)
{
    map<int, int> res;
    for (auto it = mp1.begin(); it != mp1.end(); it ++) {
        res[it->first] = it->second;
    }
    for (auto it = mp2.begin(); it != mp2.end(); it ++) {
        if (res.find(it->first) != res.end()) {
            res[it->first] += it->second;
        } else {
            res[it->first] = it->second;
        }
    }
    return res;
}

map<int, int> Subtraction(map<int, int> mp1, map<int, int> mp2)
{
    map<int, int> res;
    for (auto it = mp1.begin(); it != mp1.end(); it ++) {
        res[it->first] = it->second;
    }
    for (auto it = mp2.begin(); it != mp2.end(); it ++) {
        if (res.find(it->first) != res.end()) {
            res[it->first] -= it->second;
        } else {
            res[it->first] = -it->second;
        }
    }
    return res;
}

int main()
{
    cin >> n >> m >> t;
    for (int i = 1; i <= n; i ++) {
        int a, b;
        cin >> a >> b;
        mp1[b] = a;
    }
    for (int i = 1; i <= m; i ++) {
        int a, b;
        cin >> a >> b;
        mp2[b] = a;
    }
    map<int, int> res;
    if (!t) {
        res = Addition(mp1, mp2);
    } else {
        res = Subtraction(mp1, mp2);
    }
    int f = 0;
    for (auto it = res.begin(); it != res.end(); it ++) {
        if (it->second != 0) {
            f = 1;
            break;
        }
    }
    if (!f) {
        cout << "0";
        return 0;
    }
    int flag = 0;
    for (auto it = res.begin(); it != res.end(); it ++) {
        if (it->second == 0) {
            continue;
        }
        if (flag == 0 && it->second < 0) {
            cout << "-";
        } else if (flag != 0 && it->second > 0) {
            cout << "+";
        }
        if (it->first == 0) {
            cout << it->second;
        } else if (it->first == 1) {
            if (it->second == 1) {
                cout << "x";
            } else if (it->second == -1) {
                cout << "-x";
            } else {
                cout << it->second << "x";
            }
        } else {
            if (it->second == 1) {
                cout << "x^" << it->first;
            } else if (it->second == -1) {
                cout << "-x^" << it->first;
            } else {
                cout << it->second << "x^" << it->first;
            }
        }
        flag = 1;
    }
    return 0;
}
#include <bits/stdc++.h>

using namespace std;

int n, m, t;
map<int, int> mp1, mp2;

map<int, int> Addition(map<int, int> mp1, map<int, int> mp2)
{
    map<int, int> res;
    for (auto it = mp1.begin(); it != mp1.end(); it ++) {
        res[it->first] = it->second;
    }
    for (auto it = mp2.begin(); it != mp2.end(); it ++) {
        if (res.find(it->first) != res.end()) {
            res[it->first] += it->second;
        } else {
            res[it->first] = it->second;
        }
    }
    return res;
}

map<int, int> Subtraction(map<int, int> mp1, map<int, int> mp2)
{
    map<int, int> res;
    for (auto it = mp1.begin(); it != mp1.end(); it ++) {
        res[it->first] = it->second;
    }
    for (auto it = mp2.begin(); it != mp2.end(); it ++) {
        if (res.find(it->first) != res.end()) {
            res[it->first] -= it->second;
        } else {
            res[it->first] = -it->second;
        }
    }
    return res;
}

int main()
{
    cin >> n >> m >> t;
    for (int i = 1; i <= n; i ++) {
        int a, b;
        cin >> a >> b;
        mp1[b] = a;
    }
    for (int i = 1; i <= m; i ++) {
        int a, b;
        cin >> a >> b;
        mp2[b] = a;
    }
    map<int, int> res;
    if (!t) {
        res = Addition(mp1, mp2);
    } else {
        res = Subtraction(mp1, mp2);
    }
    int f = 0;
    for (auto it = res.begin(); it != res.end(); it ++) {
        if (it->second != 0) {
            f = 1;
            break;
        }
    }
    if (!f) {
        cout << "0";
        return 0;
    }
    int flag = 0;
    for (auto it = res.begin(); it != res.end(); it ++) {
        if (it->second == 0) {
            continue;
        }
        if (flag == 0 && it->second < 0) {
            cout << "-";
        } else if (flag != 0 && it->second > 0) {
            cout << "+";
        }
        if (it->first == 0) {
            cout << it->second;
        } else if (it->first == 1) {
            if (it->second == 1) {
                cout << "x";
            } else if (it->second == -1) {
                cout << "-x";
            } else {
                cout << it->second << "x";
            }
        } else {
            if (it->second == 1) {
                cout << "x^" << it->first;
            } else if (it->second == -1) {
                cout << "-x^" << it->first;
            } else {
                cout << it->second << "x^" << it->first;
            }
        }
        flag = 1;
    }
    return 0;
}