g0601_0700.s0640_solve_the_equation.Solution Maven / Gradle / Ivy
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Java-based LeetCode algorithm problem solutions, regularly updated
package g0601_0700.s0640_solve_the_equation;
// #Medium #String #Math #Simulation
public class Solution {
public String solveEquation(String equation) {
String[] eqs = equation.split("=");
int[] arr1 = evaluate(eqs[0]);
int[] arr2 = evaluate(eqs[1]);
if (arr1[0] == arr2[0] && arr1[1] == arr2[1]) {
return "Infinite solutions";
} else if (arr1[0] == arr2[0]) {
return "No solution";
} else {
return "x=" + (arr2[1] - arr1[1]) / (arr1[0] - arr2[0]);
}
}
private int[] evaluate(String eq) {
char[] arr = eq.toCharArray();
boolean f = false;
int a = 0;
int b = 0;
int i = 0;
if (arr[0] == '-') {
f = true;
i++;
}
while (i < arr.length) {
if (arr[i] == '-') {
f = true;
i++;
} else if (arr[i] == '+') {
i++;
}
StringBuilder sb = new StringBuilder();
while (i < arr.length && Character.isDigit(arr[i])) {
sb.append(arr[i]);
i++;
}
String n = sb.toString();
if (i < arr.length && arr[i] == 'x') {
int number;
if (n.equals("")) {
number = 1;
} else {
number = Integer.parseInt(n);
}
if (f) {
number = -number;
}
a += number;
i++;
} else {
int number = Integer.parseInt(n);
if (f) {
number = -number;
}
b += number;
}
f = false;
}
int[] op = new int[2];
op[0] = a;
op[1] = b;
return op;
}
}