＋とーを使った小町算の数式を全表示せよ

komachiGen.swift

#!/usr/bin/env xcrun swift

var i = 0
var s = 0
var sign : [Int] = []
var n = 0
var x = 0

sign.append(0)
for var i = 1; i <= 9; ++i {
    sign.append(-1)
}
do {
    x = 0
    n = 0
    s = 1
    for i = 1; i <= 9; i++ {
        if (sign[i] == 0) {
            n = 10 * n + i
        } else {
            x += s * n
            s = sign[i]
            n = i
        }
    }
    x += s * n
    if (x == 100) {
        for i = 1; i <= 9; i++ {
            if        (sign[i] ==  1) {
                    print(" + ")
            } else if (sign[i] == -1) {
                    print(" - ")
            }
            print(i)
        }
        println(" = 100")
    }
    i = 9
    s = sign[i] + 1
    while ( s > 1 ) {
        sign[i] = -1
        i--
        s = sign[i] + 1
    }
    sign[i] = s;
} while ( sign[1] < 1 )