leetcode640求解方程C++代码

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原创最新推荐文章于 2026-05-31 15:10:39 发布 327 阅读 AI 写同款· GEO 优化 ›

C++求解一元三次方程代码自己测的没问题，在CSCD博客上下载来自己用，发现有问题，自己修改后没问题了。立即下载

class Solution {
public:
    string solveEquation(string equation) {
        int x=0,num=0,t=1;
        int i=-1,j=0;
        equation.push_back('+');
        while(j<equation.size()){
           // cout<<"j"<<j<<endl;
            if(equation[j]=='+'||equation[j]=='-'||equation[j]=='='){
                if(j>=1&&equation[j-1]=='x'){
                    if(j-i-2==0){
                        if(i>=0&& equation[i]=='-') x-=t;
                        else x+=t;
                    } 
                    else{
                        if(i>=0&& equation[i]=='-') x-=t*atoi(equation.substr(i+1,j-i-2).c_str());
                        else x+=t*atoi(equation.substr(i+1,j-i-2).c_str());
                    } 
                }else{
                    if(i>=0&&equation[i]=='-') num-=t*atoi(equation.substr(i+1,j-i-1).c_str());
                    else num+=t*atoi(equation.substr(i+1,j-i-1).c_str());
                } 
                if(equation[j]=='=')  t=-1;
                i=j;
            }
            ++j;
            //cout<<x<<" "<<num<<endl;
        }
        if(x==0){
            if(num==0) return "Infinite solutions";
            else return "No solution";
        }
        return "x="+to_string(-num/x);
    }
};

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