package class38;

public class Code03_MSumToN {

public static boolean isMSum1(int num) {

for (int start = 1; start <= num; start++) {

int sum = start;

for (int j = start + 1; j <= num; j++) {

if (sum + j > num) {

break;

}

if (sum + j == num) {

return true;

}

sum += j;

}

}

return false;

}

public static boolean isMSum2(int num) {

//

// return num == (num & (~num + 1));

//

// return num == (num & (-num));

//

//

return (num & (num - 1)) != 0;

}

public static void main(String[] args) {

for (int num = 1; num < 200; num++) {

System.out.println(num + " : " + isMSum1(num));

}

System.out.println("test begin");

for (int num = 1; num < 5000; num++) {

if (isMSum1(num) != isMSum2(num)) {

System.out.println("Oops!");

}

}

System.out.println("test end");

}

}