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My answer(这个方法只适用于这个情况：15人中有14人退出，这个方法求的是最后退出人的编号，而不是剩下来的人的编号): if (ring[nextstart]) counter++, nextstart+=(counter==0)?1:0, nextstart+=(counter==N)?0:1; else nextstart=(nextstart>=TOTAL-1)?0:(nextstart+1);

my answser, based on NE's code, added some printfs for test, tested under VC.net2k3(since i am not familiar with java) still, i have a question on this problem, the man start counting. here is a result with N = 9 Result for N = 9 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 1th round (nextstart 9 ): 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 2th round (nextstart 4 ): 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 3th round (nextstart 0 ): 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 4th round (nextstart 12 ): 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 5th round (nextstart 10 ): 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 1, 6th round (nextstart 8 ): 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 1, 7th round (nextstart 11 ): 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 8th round (nextstart 13 ): 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 9th round (nextstart 1 ): 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 10th round (nextstart 5 ): 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 11th round (nextstart 2 ): 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 12th round (nextstart 3 ): 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 13th round (nextstart 14 ): 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 14th round (nextstart 6 ): 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, u could see that although the first 0 is labled 9 respected to nextstart ( 9 here ), but we counted 10 times in fact. // Exp01.cpp : Defines the entry point for the console application. // #include <stdio.h> const int TOTAL=15; int T(int N) { int ring[TOTAL] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1}; int nextstart = 0,counter=0; // for the title printf(" Result for N = %-10d",N); for(int j = 0;j<TOTAL;j++) { printf("%2d ",j); } putchar('\n'); // insert code end for (int i = 1; i<TOTAL; i++) { counter = 0; while(counter < N) { if ( ( counter == N - 1 ) || ring[nextstart] != 0 ) ( nextstart = (nextstart + 1) % TOTAL ) , counter += ( counter == N - 1 ) ? ( ( ring[nextstart] == 1 ) ? 1:0 ) : 1; else nextstart = (nextstart + 1) % TOTAL; } // since nextstart is the pointer to the one who was unlucky, // so we must make sure that ring[nextstart] always be 1 when we come here // so how we make sure? // when counter == N - 1 we should have ring[(nextstart + 1) % TOTAL] == 1 // and if we hold N - 1 in counter all the time then we got an unlimited loop! ring[nextstart] = 0; // output result for each round printf("%2dth round (nextstart %2d ): ",i,nextstart); for(int j = 0;j<TOTAL;j++) { printf(" %d,",ring[j]); } putchar('\n'); // end } return nextstart +1; } int main(void) { for(int i = 1;i< 30;i++) { T(i); putchar('\n'); } return 0; }

my answer is not so complicated. here is my answer(after fixed): if (ring[nextstart] == 0) nextstart = (nextstart + 1) % TOTAL; else [color=red]++counter, nextstart = (counter == N) ? nextstart : (nextstart + 1) % TOTAL;[/color] be careful the red line. i don't know whether it's compiler-dependent. 【 在 alexxin 的大作中提到: 】 : my answser, based on NE's code, : added some printfs for test, : tested under VC.net2k3(since i am not familiar with java) : ...................

int xxxx(int N) { int ring[TOTAL] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1}; // int ring[TOTAL] = {1,1,1,1,1}; int nextstart = 0,counter=0; for (int i = 1; i<TOTAL; i++) { counter = 0; //printf("%d is at beginning \n",nextstart); while(counter < N) { if (ring[nextstart%TOTAL]== 1) { nextstart=nextstart%TOTAL+1; counter++; if(counter == N) { nextstart--; } } else { nextstart=nextstart%TOTAL+1; } } ring[nextstart] = 0; printf("!!!!!!!!!!!!!!!! [%d] is out\n",nextstart+1); } return nextstart +1; } TOTAL=15 N =5输出： !!!!!!!!!!!!!!!! [5] is out !!!!!!!!!!!!!!!! [10] is out !!!!!!!!!!!!!!!! [15] is out !!!!!!!!!!!!!!!! [6] is out !!!!!!!!!!!!!!!! [12] is out !!!!!!!!!!!!!!!! [3] is out !!!!!!!!!!!!!!!! [11] is out !!!!!!!!!!!!!!!! [4] is out !!!!!!!!!!!!!!!! [14] is out !!!!!!!!!!!!!!!! [9] is out !!!!!!!!!!!!!!!! [8] is out !!!!!!!!!!!!!!!! [13] is out !!!!!!!!!!!!!!!! [2] is out !!!!!!!!!!!!!!!! [7] is out

如果最后一个填空非要用一条语句完成的，可以写成 nextstart = (（＋＋count）＝＝N) ? nextstart : (nextstart + 1) % TOTAL;