求一个javascript描述的解决方案

问题描述

问 题

Solve a given equation and return the value of x in the form of string "x=#value". The equation contains only '+', '-' operation, the variable x and its coefficient.

    If there is no solution for the equation, return "No solution".

    If there are infinite solutions for the equation, return "Infinite solutions".

    If there is exactly one solution for the equation, we ensure that the value of x is an integer.

    

Example 1:
   Input: "x+5-3+x=6+x-2"
    Output: "x=2"

Example 2:
            Input: "x=x"
            Output: "Infinite solutions"
            Example 3:
    
                Input: "2x=x"
                Output: "x=0"
                Example 4:
        
                    Input: "2x+3x-6x=x+2"
                    Output: "x=-1"<
                    Example 5:
                
                        Input: "x=x+2"
                        Output: "No solution"

有什么javascript描述的解决方案

解决方案

        var solveEquation = function(equation) {
                 let leftValue=0;
                let countOfLeftX = 0;
                let rightValue=0;
                let countOfRightX=0;
                let isLeft=true;
                let lastOperator='+';
                let temp='';
                for(let i=0;i<=equation.length;i++){
                    if(isLeft){
                        if(equation[i]==='+' || equation[i]==='-' || equation[i]==='='){
                            if(temp.length>0){
                                if(!!~temp.indexOf('x')){
                                    let v = temp.substring(0,temp.length-1);
                                    if(!v){
                                        v=1;
                                    }
                                    countOfLeftX = countOfLeftX +(lastOperator==='+'?+parseFloat(v):-parseFloat(v));
                                    
                                } else {
                                    leftValue = leftValue + (lastOperator==='+'?+parseFloat(temp):-parseFloat(temp));
                                }
                                temp = '';
                            } 
                            lastOperator = equation[i];

                        } else {
                            temp+=equation[i];
                        }
                        if(equation[i]==='='){
                            lastOperator='+';
                            isLeft=false;
                        }

                    } else {
                        if(equation[i]==='+' || equation[i]==='-' || i==equation.length){
                            if(temp.length>0){
                                if(!!~temp.indexOf('x')){
                                    let v = temp.substring(0,temp.length-1);
                                    if(!v){
                                        v=1;
                                    }
                                    countOfRightX = countOfRightX +(lastOperator==='+'?+parseFloat(v):-parseFloat(v));
                                    
                                } else {
                                    rightValue = rightValue + (lastOperator==='+'?+parseFloat(temp):-parseFloat(temp));
                                }
                                temp = '';
                            } 
                            if(i!==equation.length){
                                lastOperator = equation[i];
                            }
                            

                        } else {
                            temp+=equation[i];
                        }
                    }

                }
                let count = countOfLeftX - countOfRightX;
                let value = rightValue - leftValue;
                if(count ===0 && value===0){
                    return "Infinite solutions";
                } else if(count ===0 && value!==0){
                    return "No solution";
                } else {
                    return "x="+value/count;
                }
            };

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