hdu1308 What Day Is It

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本题题目描述略坑 大意是1752.9.2前美国日期用旧算法，9.14后用新算法

另外1.1.1是星期六是什么设定。。算出天数需要减2

旧历日期=year*365+M[month]+day+year/4-2

新历日期=year*365+year/4-year/100+year/400+M[month]+day+1752/100-1752/400-11-2

=year*365+year/4-year/100+year/400+M[month]+day

February写成Fabruary半天没看出来。。

代码：

#include <iostream>

#include <cstdio>

using namespace std;

int MM[12]={31,28,31,30,31,30,31,31,30,31,30,31};

int M[12]={0,31,59,90,120,151,181,212,243,273,304,334};

char MN[12][20]={"January","February","March","April","May","June","July","August","September","October","November","December"};

char DN[7][20]={"Monday","Tuesday","Wednesday","Thursday","Friday","Saturday","Sunday"};

bool leapyear(int y){

if(y<=1752)

return y%4==0;

return ((y%4==0)&&(y%100!=0))||y%400==0;

}

bool isvalid(int y,int m,int d){

if(!m||!d||!y)

return 0;

if(m>12)

return 0;

if(y==1752&&m==9&&d>2&&d<14)

return 0;

if(leapyear(y)){

if(m==2){

if(d>29)

return 0;

}

else if(d>MM[m-1])

return 0;

}

else if(d>MM[m-1]){

return 0;

}

return 1;

}

int main()

{

//freopen("input.txt","r",stdin);

int y,m,d;

int totday,curday;

while(cin>>m>>d>>y,m||d||y){

if(!isvalid(y,m,d)){

printf("%d/%d/%d is an invalid date.\n",m,d,y);

continue;

}

if(y<1752||(y==1752&&m<9)||(y==1752&&m==9&&d<=2)){

totday=(y-1)*365+(y-1)/4;//-(y-1)/100+(y-1)/400;

totday+=M[m-1];

totday+=d;

if(y%4==0&&m>2){

totday++;

}

totday-=2;

curday=totday%7;

}

else{

totday=(y-1)*365+(y-1)/4-(y-1)/100+(y-1)/400;

totday+=M[m

-1];

totday+=d;

if(leapyear(y)&&m>2){

totday++;

}

curday=totday%7;

}

if(curday==0)

curday=7;

// cout<<curday<<endl;

printf("%s %d, %d is a %s\n",MN[m-1],d,y,DN[curday-1]);

}

return 0;

}