boolean[] solve(int a[], char signs[], int b[], int[] c) {
        boolean ans[] = new boolean[a.length];
        for (int i = 0; i < a.length; i++) {
            if (signs[i] == '+') {
                ans[i] = a[i] + b[i] == c[i];
            } else {
                ans[i] = a[i] - b[i] == c[i];
            }
        }
        return ans;
    }