hihocoder1148https://hihocoder.com/problemset/problem/1148
因为题目没有给范围，我本来是这么写的。
1 for(int i = 0; i <= 10000; i++){ 2 if(i%4==0&&i%100!=0||i%400==0){ 3 cnt++; 4 } 5 memo[i] = cnt; 6 }
然后RE了，事实证明长度还是很大的。
本题的关键在于利用计算闰年的方法巧妙地实现类似以上的计数。
1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 #include<cstdlib> 6 #include<string> 7 #include<cmath> 8 #include<vector> 9 #include<stack> 10 #include<iterator> 11 #include<queue> 12 #include<cctype> 13 #include<map> 14 #define lson l, m, rt<<1 15 #define rson m+1, r, rt<<1|1 16 #define IO ios::sync_with_stdio(false);cin.tie(0); 17 #define INF 0x3f3f3f3f 18 #define MAXN 100010 19 const int MOD=1e9+7; 20 typedef long long ll; 21 using namespace std; 22 int n, d1, d2, yy1, y2; 23 char s1[110], s2[110]; 24 map<string, int> mp; 25 int main() 26 { 27 cin >> n; 28 int kase=0, cnt=0; 29 mp["January"]=1;mp["February"]=2;mp["March"]=3; 30 mp["April"]=4;mp["May"]=5;mp["June"]=6; 31 mp["July"]=7;mp["August"]=8;mp["September"]=9; 32 mp["October"]=10;mp["November"]=11;mp["December"]=12; 33 for(int i = 0; i < n; i++){ 34 cnt=0; 35 scanf("%s %d, %d", s1, &d1, &yy1); 36 scanf("%s %d, %d", s2, &d2, &y2); 37 if(yy1 != y2){ 38 //容斥的感觉 39 int k1 = yy1/4-yy1/100+yy1/400; 40 int k2 = (y2-1)/4-(y2-1)/100+(y2-1)/400; 41 cnt=k2-k1; 42 43 if(yy1%4==0&&yy1%100!=0||yy1%400==0){ 44 if(mp[s1] <= 2){ 45 cnt++; 46 } 47 } 48 if(y2%4==0&&y2%100!=0||y2%400==0){ 49 if(mp[s2] > 2||mp[s2]==2&&d2==29){ 50 cnt++; 51 } 52 } 53 } 54 else{ 55 if(yy1%4==0&&yy1%100!=0||yy1%400==0){ 56 if((mp[s1] <= 2)&&(mp[s2]>2||mp[s2]==2&&d2==29)) 57 cnt++; 58 } 59 } 60 cout << "Case #" << ++kase << ": "; 61 cout << cnt << endl; 62 } 63 return 0; 64 }