题意：
给出东八区的时间，求另一个时区的时间。
思路：
把时间转成分钟表示，东八区转化成零时区，在转化成对应时区。
代码：
#include <iostream>
#include <iomanip>
#include <algorithm>
#include <cstring>
#include <cctype>
#include <cstdlib>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <map>
#include <list>
#include <set>
#include <stack>
#include <queue>
#include <string>
#include <sstream>
#define pb push_back
#define X first
#define Y second
#define lch (o<<1)
#define rch (o<<1|1)
#define ALL(x) x.begin(),x.end()
#define INS(x) inserter(x,x.begin())
#define pii pair<int,int>
#define qclear(a) while(!a.empty())a.pop();
#define lowbit(x) (x&-x)
#define sd(n) scanf("%d",&n)
#define sdd(n,m) scanf("%d%d",&n,&m)
#define sddd(n,m,k) scanf("%d%d%d",&n,&m,&k)
#define mst(a,b) memset(a,b,sizeof(a))
#define cout3(x,y,z) cout<<x<<" "<<y<<" "<<z<<endl
#define cout2(x,y) cout<<x<<" "<<y<<endl
#define cout1(x) cout<<x<<endl
#define IOS std::ios::sync_with_stdio(false)
#define SRAND srand((unsigned int)(time(0)))
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int uint;
using namespace std;
const double PI=acos(-1.0);
const int INF=0x3f3f3f3f;
const ll mod=1e9+7;
const double eps=1e-8;
const int maxn=3005;
const int maxm=10005;
int n,m;
char str[10];
void solve() {
int t;
sd(t);
int aday=24*60;
while(t--){
scanf("%d%d%s",&n,&m,str);
int t1=n*60+m;
t1-=8*60;
t1=((t1%aday)+aday)%aday;
int t2=0;
int s=1;
if(str[3]=='-')s=-1;
int now1=0,now2=0;
int i;
for(i=4;;i++){
if(str[i]=='\0'||str[i]=='.')break;
now1=now1*10+str[i]-'0';
}
if(str[i]!='\0'){
i++;
now2=str[i]-'0';
}
t2=s*(now1*60+now2*6);
t1+=t2;
t1=((t1%aday)+aday)%aday;
int hh,mm;
hh=t1/60;
mm=t1%60;
printf("%02d:%02d\n",hh,mm);
}
return ;
}
int main() {
#ifdef LOCAL
freopen("in.txt","r",stdin);
// freopen("out.txt","w",stdout);
#else
// freopen("","r",stdin);
// freopen("","w",stdout);
#endif
solve();
return 0;
}