用C语言代码实现编写一个四叉树

我可以回答这个问题。四叉树是一种数据结构，它可以用于空间划分和查询。以下是一个简单的C语言代码实现：

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

#define MAX_POINTS 10

typedef struct point {
    int x;
    int y;
} Point;

typedef struct quadtree {
    Point point;
    struct quadtree* nw;
    struct quadtree* ne;
    struct quadtree* sw;
    struct quadtree* se;
} Quadtree;

Quadtree* create_quadtree(int x1, int y1, int x2, int y2) {
    Quadtree* quadtree = (Quadtree*)malloc(sizeof(Quadtree));
    quadtree->point.x = (x1 + x2) / 2;
    quadtree->point.y = (y1 + y2) / 2;
    quadtree->nw = NULL;
    quadtree->ne = NULL;
    quadtree->sw = NULL;
    quadtree->se = NULL;
    return quadtree;
}

void insert_point(Quadtree* quadtree, Point point) {
    if (quadtree == NULL) {
        return;
    }
    if (quadtree->nw == NULL && quadtree->ne == NULL && quadtree->sw == NULL && quadtree->se == NULL) {
        quadtree->point = point;
        return;
    }
    if (point.x < quadtree->point.x && point.y < quadtree->point.y) {
        if (quadtree->nw == NULL) {
            quadtree->nw = create_quadtree(0, 0, quadtree->point.x, quadtree->point.y);
        }
        insert_point(quadtree->nw, point);
    } else if (point.x >= quadtree->point.x && point.y < quadtree->point.y) {
        if (quadtree->ne == NULL) {
            quadtree->ne = create_quadtree(quadtree->point.x, 0, MAX_POINTS, quadtree->point.y);
        }
        insert_point(quadtree->ne, point);
    } else if (point.x < quadtree->point.x && point.y >= quadtree->point.y) {
        if (quadtree->sw == NULL) {
            quadtree->sw = create_quadtree(0, quadtree->point.y, quadtree->point.x, MAX_POINTS);
        }
        insert_point(quadtree->sw, point);
    } else {
        if (quadtree->se == NULL) {
            quadtree->se = create_quadtree(quadtree->point.x, quadtree->point.y, MAX_POINTS, MAX_POINTS);
        }
        insert_point(quadtree->se, point);
    }
}

void print_quadtree(Quadtree* quadtree) {
    if (quadtree == NULL) {
        return;
    }
    printf("(%d, %d)\n", quadtree->point.x, quadtree->point.y);
    print_quadtree(quadtree->nw);
    print_quadtree(quadtree->ne);
    print_quadtree(quadtree->sw);
    print_quadtree(quadtree->se);
}

int main() {
    Quadtree* quadtree = create_quadtree(0, 0, MAX_POINTS, MAX_POINTS);
    Point points[MAX_POINTS] = {{1, 2}, {3, 4}, {5, 6}, {7, 8}, {9, 10}, {11, 12}, {13, 14}, {15, 16}, {17, 18}, {19, 20}};
    for (int i = 0; i < MAX_POINTS; i++) {
        insert_point(quadtree, points[i]);
    }
    print_quadtree(quadtree);
    return 0;
}

这个代码实现了一个简单的四叉树，可以插入点并打印整个四叉树。