this.expr = expr;
}
/*
(操作符1)
/ \
(操作符2) (操作数4)
/ \
(操作符3) (操作数3)
/ \
(操作数1) (操作数2)
*/
private int tree1[] = new int[7];; // 存放第一棵树
//private int tree2[]; // 存放第二棵树
private final int PLUS = 1; // 加
private final int MINUS = 2; // 减
private final int MULT = 3; // 乘
private final int DIV = 4; // 除
/**
* 计算24点的主函数
*/
public void calculate(int a, int b, int c, int d) {
int data[] = { a, b, c, d };
// 1.用数组构建一棵树，其中0,1,3处填操作符；2,4,5,6填充操作数
// 2.按照参数a,b,c,d不同顺序填充树，+-*/也填充
for (int h = 0; h < 4; h++) {
for (int i = 0; i < 4; i++) {
if (i == h) {
continue;
}
for (int j = 0; j < 4; j++) {
if (j == i || j == h) {
continue;
}
for (int k = 0; k < 4; k++) {
if (k == h || k == i || k == j) {
continue;
tree1[2] = data[h];
tree1[4] = data[i];
tree1[5] = data[j];
tree1[6] = data[k];
// 填充操作符
for (int m = PLUS; m <= DIV; m++) {
for (int n = PLUS; n <= DIV; n++) {
for (int o = PLUS; o <= DIV; o++) {
tree1[0] = m;
tree1[1] = n;
tree1[3] = o;
String t[] = new String[4];
for (int z = 0; z < 4; z++) {
switch (tree1[z]) {
case PLUS:
t[z] = "+";
break;
case MINUS:
t[z] = "-";
break;
case MULT:
t[z] = "*";
break;
case DIV:
t[z] = "/";
break;
}
}
// 目前为止tree数组全部已赋值
String postexpr = tree1[5] + " " + tree1[6]
+ " " + t[3] + " " + tree1[4] + " "
+ t[1] + " " + tree1[2] + " " + t[0];
String result = CalculatorUtils
.calculateReversePolish(postexpr);
if (Double.parseDouble((result)) == 24.0) {
expr = "(((" + tree1[5] + t[3] + tree1[6]
+ ")" + t[1] + tree1[4] + ")"
+ t[0] + tree1[2] + ")";