Star Code

#include <stdio.h>

int main(void)
{
	double realCoord, imagCoord;
	double realTemp,  imagTemp, realTemp2, arg;
	int    iterations;
	
	for(imagCoord = 1.2; imagCoord >= -1.2; imagCoord -= 0.05)
	{
		for(realCoord = -0.6; realCoord <= 1.77; realCoord += 0.03)
		{
			iterations = 0;
			realTemp   = realCoord; imagTemp = imagCoord;
			arg        = realCoord*realCoord + imagCoord*imagCoord;
			
			for(; arg<4 && iterations<40; ++iterations)
			{
				realTemp2 = realTemp*realTemp - imagTemp*imagTemp - realCoord;
				imagTemp  = 2*realTemp*imagTemp - imagCoord;
				realTemp  = realTemp2;
				arg       = realTemp*realTemp + imagTemp*imagTemp;	
			}
			
			switch (iterations % 4)
			{
				case 0: putchar('.'); break;
				case 1: putchar('o'); break;
				case 2: putchar('O'); break;
				case 3: putchar('@'); break;
			}
		}
		putchar(10);
	}
	return 0;
}

#include <stdio.h>

static int upperlim, sum; 

void binqueen(int row, int ld, int rd)
{
    int pos, p;
    if(row != upperlim)
    {
        pos = upperlim & ~(row | ld | rd);
        while (pos)
        {
            p = pos & -pos;
            pos -= p;
            binqueen(row+p, (ld+p)<<1, (rd+p)>>1);
        }
    }
    else sum++;
}


int main(void)
{
    int n;
    scanf("%d", &n);
    upperlim = (1<<n) - 1;
    binqueen(0, 0, 0);
    printf("%d", sum);
    return 0;
}

#include <stdio.h>
int C[101][101], len[101];

int main(void)
{
	int i, j, r, t, l;
	C[0][0] = 1;
	len[0]  = 1;
	l       = 1;        //长度
	
	for(i = 1; i <= 100; ++i)
	{
		for(j = 0; j < l; ++j)        //乘法
			C[i][j] = C[i-1][j] * (4*i-2);
		for(r=j = 0; j < l; ++j)
		{
			t       = C[i][j] + r;
			C[i][j] = t % 10;
			r       = t / 10;
		}
		while(r)
			C[i][l++] = r % 10, r /= 10;
		for(j = l-1, r = 0; j >= 0; --j)        //除法
		{
			t       = r*10 + C[i][j];
			C[i][j] = t / (i+1);
			r       = t % (i+1);
		}
		while(!C[i][l-1])
			--l;
		len[i] = l;
	}
			
	for(i = 1; i <= 100; ++i)
	{
		printf("%d:", i);
		for(j = len[i]-1; j >= 0; --j)
			printf("%d", C[i][j]);
		putchar(10);
	}
	
	return 0;
}

根据康托展开公式：

a[i]为第i个数比后面的都小的个数。

#include <stdio.h>
#include <string.h>
int FAC[10] = {1,1,2,6,24,120,720,5040,40320,362880};
int CantorExp(char *s, int n)
{
	int i, j, t, num = 0;
	for(i = 0; i < n; ++i)
	{
		t = 0;
		for(j = i+1; j < n; ++j)
			if(s[j] < s[i])
				++t;
		num += FAC[n-i-1]*t;
	}
	return num+1;
}
int main(int argc, char *argv[])
{
	char s[] = "1324";	//输入一个排列数的字符串序列 
	printf("%d", CantorExp(s, strlen(s)));
	return 0;
}

对于平面上N个点，求其中两个距离最近的点。输入格式：点的个数N，然后是N个坐标即可计算出。

#include <stdio.h>
#include <math.h>
#include <assert.h>
#include <stdlib.h>

struct pos {double x, y;};
typedef struct pos Pos;
Pos p[100000];
int d[100000];
double eps = 0.00001;

int cmp_x(const void *p, const void *q)
{
	double tmp=((Pos*)p)->x-((Pos*)q)->x;
	if(tmp>0) return 1;
	else if(fabs(tmp)<eps) return 0;
	else return -1;
}

double Dest(Pos p2, Pos p1)
{
    return ((p2.y-p1.y)*(p2.y-p1.y)+(p2.x-p1.x)*(p2.x-p1.x));
}

double Min(double a, double b)
{
    return a < b ? a : b;
}

int cmp(const void *a, const void *b)
{
     return(*(int *)a-*(int *)b);
}

double NSP(int left, int right)
{
    double m1, m2, m3 , res;
    int i, j, ix, mid;
    if(right - left == 1)
        return Dest(p[right], p[left]);
    else if(right - left == 2)
    {
        m1 = Dest(p[left], p[left+1]);
        m2 = Dest(p[left], p[left+2]);
        m3 = Dest(p[left+1], p[left+2]);
        return Min(m1, Min(m2, m3));
    }
    mid = (left+right)/2;
    res = Min(NSP(left, mid), NSP(mid+1, right));
    
    ix = 0;
    for(i = mid; i>=left && p[mid].x-p[i].x < res; --i)
        d[ix++] = i;
    for(i = mid+1; i<=right && p[i].x-p[mid+1].x < res; ++i)
        d[ix++] = i;
    qsort(d, ix, sizeof(d[0]), cmp);
    for(i = 0; i < ix; ++i)
        for(j = i+1; j<ix && j<i+4 && p[d[j]].y-p[d[i]].y < res; ++j)
            res = Min(res, Dest(p[d[j]], p[d[i]])); 
    return res;
}

int main(void)
{
    int N, i;
    while(scanf("%d", &N), N)
    {
    	assert(N!=1 && N<100000);
        for(i = 0; i < N; ++i)
            scanf("%lf %lf", &p[i].x, &p[i].y);
            
        qsort(p, N, sizeof(p[0]), cmp_x);
        printf("%.2lf\n", sqrt(NSP(0, N-1)));
    }
    return 0;
}

用的是分治法。