如何找出那个苹果【原创】

网上看到的题目：有12苹果，其中有1个与其余的11个都不同，可能比其它的重，也可能比其他的轻。现在给出一个没有砝码的天平，要求称量3次找出这个苹果，并且判断其轻重情况！

我测试的情况是：称量3次是可以找到这个苹果。

#include <stdio.h>

#define N 12

int fapp(int apple[]);

int main(int argc, char *argv[])
{
        int index = 0;
        int apple[N] = {0};

        for (index = 0; index < N; index++) {
                for (int i = 0; i < N; i++) {
                        apple[i] = 5;
                }
                apple[index] = 1;
                fapp(apple);
                apple[index] = 9;
                fapp(apple);
                printf("End test-%d\n\n", index);
        }
}

int fapp(int apple[])
{
        int index = 0;
        int partA, partB, partC;

        /* partition the apples to three parts averagely */
        partA = apple[0] + apple[1] + apple[2]  + apple[3];
        partB = apple[4] + apple[5] + apple[6]  + apple[7];
        partC = apple[8] + apple[9] + apple[10] + apple[11];

        if (partA == partB) {/* weigh A&B for 1st time */
                /* The unusual apple in partC, get 3 apples from partC, weight for 2nd time */
                if (apple[8] + apple[9] + apple[10] == apple[0] + apple[1] + apple[2]) {
                        /* unusual apple is last, weight for 3rd time */
                        if (apple[8] > apple[11]) {
                                printf("The last apple is unusual, weight = %d, light.\n", apple[11]);
                        } else {
                printf("The last apple is unusual, weight = %d, weighter.\n", apple[11]);
            }
                } else if (apple[8] + apple[9] + apple[10] > apple[0] + apple[1] + apple[2]) {
                        if (apple[8] == apple[10]) {
                                printf("The apple 9 is unusual, weighter,  weight = %d\n", apple[9]);
                        } else if (apple[8] > apple[10]) {
                                printf("The apple 8 is unusual, weighter, weight = %d\n", apple[8]);
                        } else {
                printf("The apple 10 is unusual, weighter, weight = %d\n", apple[10]);
            }
                } else { /* apple[8] + apple[9] + apple[10] < apple[0] + apple[1] + apple[2] */
                        if (apple[8] == apple[10]) {
                                printf("The apple 9 is unusual, light, weight = %d\n", apple[9]);
                        } else if (apple[8] > apple[10]) {
                                printf("The apple 10 is unusual, light, weight = %d\n", apple[10]);
                        } else {
                printf("The apple 8 is unusual, light, weight = %d\n", apple[8]);
            }
                }
        } else if (partA > partB) {
                /* The unusual apple in partA or partB, all partC apples is usual */
                /* partition partA/B to 3 parts, a0,a1,b0; a2,a3,b1; b2,b3 */
                if (apple[0]+apple[1]+apple[4] == apple[2]+apple[3]+apple[5]) { /* weight 2nd time */
                        /* unusual apple is one of b2,b3 */
                        if (apple[6] == apple[8]) { /* weight 3rd time */
                                printf("The apple 7 is unusual, weight = %d, light than others\n", apple[7]);
                        } else {
                                printf("The apple 6 is unusual, weight = %d, light than others\n", apple[6]);
                        }
                } else if (apple[0]+apple[1]+apple[4] > apple[2]+apple[3]+apple[5]) {
                        }
                } else if (apple[0]+apple[1]+apple[4] > apple[2]+apple[3]+apple[5]) {
                        /* if unusual apple is weighter, then is one of a0,a1 */
                        /* if unusual apple is light, then is b1 */
                        if (apple[0] == apple[1]) {
                                printf("The apple 5 is unusual, weight = %d, light than others\n", apple[5]);
                        } else if (apple[0] > apple[1]) {
                                printf("The apple 0 is unusual, weight = %d, weighter than others\n", apple[0]);
                        }  else {
                                printf("The apple 1 is unusual, weight = %d, weighter than others\n", apple[1]);
                        }
                } else { /* apple[0]+apple[1]+apple[4] < apple[2]+apple[3]+apple[5] */
                        /* if unusual apple is weighter, then is one of a2,a3 */
                        /* if unusual apple is light, then is b0 */
                        if (apple[2] == apple[3]) {
                                printf("The apple 4 is unusual, weight = %d, light than others\n", apple[4]);
                        } else if (apple[2] > apple[3]) {
                                printf("The apple 2 is unusual, weight = %d, weighter than others\n", apple[2]);
                        }  else {
                                printf("The apple 3 is unusual, weight = %d, weighter than others\n", apple[3]);
                        }
                }
        } else { /* partA < partB */
                /* The unusual apple in partA or partB, all partC apples is usual */
                /* partition partA/B to 3 parts, a0,a1,b0; a2,a3,b1; b2,b3 */
                if (apple[0]+apple[1]+apple[4] == apple[2]+apple[3]+apple[5]) { /* weight 2nd time */
                        /* unusual apple is one of b2,b3 */
                        if (apple[6] == apple[8]) { /* weight 3rd time */
                                printf("The apple 7 is unusual, weight = %d, weighter than others\n", apple[7]);
                        } else {
                                printf("The apple 6 is unusual, weight = %d, weighter than others\n", apple[6]);
                        }
                } else if (apple[0]+apple[1]+apple[4] > apple[2]+apple[3]+apple[5]) {
                        /* if unusual apple is light, then is one of a2,a3 */
                        /* if unusual apple is weight, then is b0 */
                        if (apple[2] == apple[3]) {
                                printf("The apple 4 is unusual, weight = %d, weighter than others\n", apple[4]);
                        } else if (apple[2] > apple[3]) {
                                printf("The apple 3 is unusual, weight = %d, light than others\n", apple[3]);
                        }  else {
                                printf("The apple 2 is unusual, weight = %d, light than others\n", apple[2]);
                        }
                } else { /* apple[0]+apple[1]+apple[4] < apple[2]+apple[3]+apple[5] */
                        /* if unusual apple is light, then is one of a0,a1 */
                        /* if unusual apple is weight, then is b1 */
                        /* if unusual apple is light, then is one of a0,a1 */
                        /* if unusual apple is weight, then is b1 */
                        if (apple[0] == apple[1]) {
                                printf("The apple 5 is unusual, weight = %d, weighter than others\n", apple[5]);
                        } else if (apple[0] > apple[1]) {
                                printf("The apple 1 is unusual, weight = %d, light than others\n", apple[1]);
                        }  else {
                                printf("The apple 0 is unusual, weight = %d, light than others\n", apple[0]);
                        }
                }
        }

}