sudo apt-get dist-upgrade 錛堟洿鏂版墍鏈夎蔣浠訛級
# Shanghai Jiaotong Unverisity. APT source for Ubuntu 8.04 (hardy heron)
deb http://ftp.sjtu.edu.cn/ubuntu/ hardy main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ hardy-backports main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ hardy-proposed main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ hardy-security main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ hardy-updates main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy-backports main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy-proposed main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy-security main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy-updates main multiverse restricted universe
# University of Science and Technology of China. APT source for Ubuntu 8.04 (hardy heron)
deb http://debian.ustc.edu.cn/ubuntu/ hardy main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ hardy-backports main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ hardy-proposed main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ hardy-security main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ hardy-updates main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ hardy main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ hardy-backports main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ hardy-proposed main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ hardy-security main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ hardy-updates main multiverse restricted universe]]>
Why is this a significant problem?
Are there alternate approaches to solve this problem?
Can we improve the techniques proposed in the paper?
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using namespace std;
bool IsRound(int year){
if((year%100)&&(year%4==0)) return 1;
if((year%100==0)&&(year%400==0)) return 1;
return 0;
}
int main() {
int n;
int year_s[2]= {365*24*60*60, 366*24*60*60};
int month_s[2][12]={{31,28,31,30,31,30,31,31,30,31,30,31},
{31,29,31,30,31,30,31,31,30,31,30,31}};
int day_s = 24*60*60;
int hour_s = 60*60;
int minute_s = 60;
while(cin>>n){
int temp = n;
int year=1970;
int month=1;
int day=1;
int hour=0;
int minute=0;
int second=0;
while(temp>=60){
int flag= IsRound(year);
if(temp>=year_s[flag]) { year++; temp-=year_s[flag]; }
else if(temp>=day_s){
int days = temp/day_s;
temp=temp%day_s;
int i=0;
int flag = IsRound(year);
int hh=31;
while(days>=hh){
days-=month_s[flag][i++];
hh=month_s[flag][i];
}
month+= i;
day+=days;
}else if(temp>=hour_s){
hour=temp/hour_s;
temp%=hour_s;
}else if(temp>=minute_s){
minute = temp/minute_s;
temp%=minute_s;
}
}
second = temp;
cout<<year<<"-";
if(month/10==0) cout<<"0";
cout<<month<<"-";
if(day/10==0) cout<<"0";
cout<<day<<" ";
if(hour/10==0) cout<<"0";
cout<<hour<<":";
if(minute/10==0) cout<<"0";
cout<<minute<<":";
if(second/10==0) cout<<"0";
cout<<second<<endl;
}
return 0;
}
]]>
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BFS O(c d ) O(c d ) Know answers are very near top of tree, or want shallowest answer.
DFS+ID O(c d) O(d) Want to do BFS, don't have enough space, and can spare the time.
d is the depth of the answer k is the depth searched d <= k Remember the ordering properties of each search. If the program needs to produce a list sorted shortest solution first (in terms of distance from the root node), use breadth first search or iterative deepening. For other orders, depth first search is the right strategy. If there isn't enough time to search the entire tree, use the algorithm that is more likely to find the answer. If the answer is expected to be in one of the rows of nodes closest to the root, use breadth first search or iterative deepening. Conversely, if the answer is expected to be in the leaves, use the simpler depth first search. Be sure to keep space constraints in mind. If memory is insufficient to maintain the queue for breadth first search but time is available, use iterative deepening.
quote from http://ace.delos.com/usacotext2?a=y9SZdbB6WeB&S=rec
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