static int open_exec_filter(struct cgit_filter *base, va_list ap)
{
struct cgit_exec_filter *filter = (struct cgit_exec_filter *)base;
int i;
for (i = 0; i < filter->base.argument_count; i++)
filter->argv[i + 1] = va_arg(ap, char *);
filter->old_stdout = chk_positive(dup(STDOUT_FILENO),
"Unable to duplicate STDOUT");
chk_zero(pipe(filter->pipe_fh), "Unable to create pipe to subprocess");
filter->pid = chk_non_negative(fork(), "Unable to create subprocess");
if (filter->pid == 0) {
close(filter->pipe_fh[1]);
chk_non_negative(dup2(filter->pipe_fh[0], STDIN_FILENO),
"Unable to use pipe as STDIN");
execvp(filter->cmd, filter->argv);
die_errno("Unable to exec subprocess %s", filter->cmd);
}
close(filter->pipe_fh[0]);
chk_non_negative(dup2(filter->pipe_fh[1], STDOUT_FILENO),
"Unable to use pipe as STDOUT");
close(filter->pipe_fh[1]);
return 0;
}
int cgit_open_filter(struct cgit_filter *filter)
{
filter->old_stdout = chk_positive(dup(STDOUT_FILENO),
"Unable to duplicate STDOUT");
chk_zero(pipe(filter->pipe_fh), "Unable to create pipe to subprocess");
filter->pid = chk_non_negative(fork(), "Unable to create subprocess");
if (filter->pid == 0) {
close(filter->pipe_fh[1]);
chk_non_negative(dup2(filter->pipe_fh[0], STDIN_FILENO),
"Unable to use pipe as STDIN");
execvp(filter->cmd, filter->argv);
die("Unable to exec subprocess %s: %s (%d)", filter->cmd,
strerror(errno), errno);
}
close(filter->pipe_fh[0]);
chk_non_negative(dup2(filter->pipe_fh[1], STDOUT_FILENO),
"Unable to use pipe as STDOUT");
close(filter->pipe_fh[1]);
return 0;
}
void dfs(int x,int y,int c){
// 如果找到了最理想结果，则不必继续搜索
if(flag) return ;
pii temp[N];
// expt表示比赛(x,y)预计要安排到的轮次数
int expt = c / tmpn;
// sum表示当前的方差和
int sum = 0;
for(int i = 1; i <= cntn; i++)
sum += differ(hash[i]);
if(sum > TMP+EPS) return;
// 此处是一个剪枝，如果继续搜索没有当前结果好，则舍弃
if(y == ANS[x].size()) x ++, y = 0;
if(x == len) {
// 搜索到终点
if(sum == TMP) {
flag = 1;
}
// 如果当前结果比最优结果好，那么记录当前结果
if(sum < best ) {
// 按照之前的要求，某行的轮空不超过1
for(int i = 1; i <= base; i++)
if(chk_zero(hash[i]) > 1)
return ;
best = sum;
memcpy(last_ans,ans,sizeof(ans));
memcpy(myconf,conf,sizeof(conf));
}
return;
}
//p是当前比赛
pii p = ANS[x][y];
int a =p.first, b = p.second;
for(int i = 0; i < coln; i++)
temp[i] = make_pair(use[i],i);
// 数组use是赛道的使用频率
sort(temp,temp+coln);
// 先从使用频率最小的赛道开始检查
for(int q = 0; q < coln; q++){
int j = temp[q].second;
hash[a][j]++;
hash[b][j]++;
use[j] ++;
// 假设选择赛道j，更新hash && use 数组
// dif是能容忍的hash值最大的最大最小值的差
int dif = coln <= 4 ? 3 : 2;
if(differ(hash[a]) <= dif && differ(hash[b]) <= dif) {
int i = expt,cost = 0;
if(ans[i][j] == zero && !_vis[a][i] && !_vis[b][i])
// tight_col是代表列数 <=2
if(tight_col || i == 0 || !conflict(ans[i-1][j],a,b)){
_vis[a][i] = 1;
_vis[b][i] = 1;
ans[i][j] = p;
dfs(x,y+1,c+1);
if(flag) return ;
_vis[a][i] = 0;
_vis[b][i] = 0;
ans[i][j] = zero;
}
}
// 搜索结束，回溯
use[j]--;
hash[a][j]--;
hash[b][j]--;
}
}
