代码如下:
#include <stdio.h>
#define MAX_DOUBLE 1.79769e+308
#define E 3struct point
{
int x, y;
};void compress()
{
FILE * fin = fopen("rand.txt", "r");
FILE * fout = fopen("out.txt", "w");
//上门和下门,初始时门是关着的
double up_gate = -MAX_DOUBLE;
double down_gate = MAX_DOUBLE;
//当前数据的上斜率和下斜率
double now_up, now_down;
int data; //当前读取到的数据
int last_read_data; //当前数据的前一个数据
int last_stored_data; //最近保存的点 //read and save the first data
fscanf(fin, "%d", &last_stored_data);
fprintf(fout, "0 %d ", last_stored_data);
last_read_data = last_stored_data;
int last_stored_t = 0; //最近保存数据的时间,init 0
//循环处理数据
int t=0;
while(++t, fscanf(fin, "%d", &data) != EOF)
{
now_up = double(data-last_stored_data-E) / (t-last_stored_t);
if(now_up > up_gate)
up_gate = now_up; now_down = double(data-last_stored_data+E) / (t-last_stored_t);
if(now_down < down_gate)
down_gate = now_down; if(up_gate >= down_gate)
{
//保存前一个点
fprintf(fout, "%d %d ", t-1, last_read_data);
last_stored_t = t-1; //修改最近保存数据时间点
last_stored_data = last_read_data;
//初始化两扇门为当前点与上个点的斜率
up_gate = double(data-last_stored_data-E);
down_gate = double(data-last_stored_data+E);
}
last_read_data = data;
}
// sava end point
fprintf(fout, "%d %d ", t-1, last_read_data);
fclose(fin);
fclose(fout);
}void uncompress()
{
FILE * fin = fopen("out.txt", "r");
FILE * fout = fopen("src.txt", "w"); point a,b;
fscanf(fin, "%d %d", &a.x, &a.y);
while(fscanf(fin, "%d %d", &b.x,&b.y) != EOF)
{
//Step.1
fprintf(fout, "%d ", a.y);
//Step.2
if(a.x+1 != b.x)
{
double k = double(b.y - a.y) / (b.x - a.x); //计算斜率
for(int i=a.x+1; i<b.x; i++)
{
//线性插值求被压缩掉的数据
fprintf(fout, "%.0lf ", k*(i-a.x) + a.y);
}
} a.x = b.x;
a.y = b.y;
}
fprintf(fout, "%d ", b.y);
fclose(fin);
fclose(fout);
}int main(void)
{
compress();
uncompress();
return 0;
}
}
#include <stdio.h>
#define MAX_DOUBLE 1.79769e+308
#define E 3struct point
{
int x, y;
};void compress()
{
FILE * fin = fopen("rand.txt", "r");
FILE * fout = fopen("out.txt", "w");
//上门和下门,初始时门是关着的
double up_gate = -MAX_DOUBLE;
double down_gate = MAX_DOUBLE;
//当前数据的上斜率和下斜率
double now_up, now_down;
int data; //当前读取到的数据
int last_read_data; //当前数据的前一个数据
int last_stored_data; //最近保存的点 //read and save the first data
fscanf(fin, "%d", &last_stored_data);
fprintf(fout, "0 %d ", last_stored_data);
last_read_data = last_stored_data;
int last_stored_t = 0; //最近保存数据的时间,init 0
//循环处理数据
int t=0;
while(++t, fscanf(fin, "%d", &data) != EOF)
{
now_up = double(data-last_stored_data-E) / (t-last_stored_t);
if(now_up > up_gate)
up_gate = now_up; now_down = double(data-last_stored_data+E) / (t-last_stored_t);
if(now_down < down_gate)
down_gate = now_down; if(up_gate >= down_gate)
{
//保存前一个点
fprintf(fout, "%d %d ", t-1, last_read_data);
last_stored_t = t-1; //修改最近保存数据时间点
last_stored_data = last_read_data;
//初始化两扇门为当前点与上个点的斜率
up_gate = double(data-last_stored_data-E);
down_gate = double(data-last_stored_data+E);
}
last_read_data = data;
}
// sava end point
fprintf(fout, "%d %d ", t-1, last_read_data);
fclose(fin);
fclose(fout);
}void uncompress()
{
FILE * fin = fopen("out.txt", "r");
FILE * fout = fopen("src.txt", "w"); point a,b;
fscanf(fin, "%d %d", &a.x, &a.y);
while(fscanf(fin, "%d %d", &b.x,&b.y) != EOF)
{
//Step.1
fprintf(fout, "%d ", a.y);
//Step.2
if(a.x+1 != b.x)
{
double k = double(b.y - a.y) / (b.x - a.x); //计算斜率
for(int i=a.x+1; i<b.x; i++)
{
//线性插值求被压缩掉的数据
fprintf(fout, "%.0lf ", k*(i-a.x) + a.y);
}
} a.x = b.x;
a.y = b.y;
}
fprintf(fout, "%d ", b.y);
fclose(fin);
fclose(fout);
}int main(void)
{
compress();
uncompress();
return 0;
}
}
解决方案 »
免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货