[Bjwc2008] Qin Teng and teaching evaluation

Doodle

 

Two points.

How can this problem be solved? I didn't come up with it.

I read the question.

Because there is only one odd point, for a position X, the sum of the teachings of the range [0, x] is obtained. If it is an odd number, the value of X is greater; otherwise, X is smaller (wonderful ).

Although the answer is within the int, L + R may blow up the int, resulting in a few points of TLE, so we should open long.

 1 #include<cstdio> 2 #include<iostream> 3 #include<cmath> 4 #include<algorithm> 5 #include<cstring> 6 #include<cstdlib> 7 #include<cctype> 8 #include<vector> 9 #include<stack>10 #include<queue>11 using namespace std;12 #define enter puts("") 13 #define space putchar(‘ ‘)14 #define Mem(a, x) memset(a, x, sizeof(a))15 #define rg register16 typedef long long ll;17 typedef double db;18 const int INF = 0x3f3f3f3f;19 const db eps = 1e-8;20 const int maxn = 2e5 + 5;21 inline ll read()22 {23     ll ans = 0;24     char ch = getchar(), last = ‘ ‘;25     while(!isdigit(ch)) {last = ch; ch = getchar();}26     while(isdigit(ch)) {ans = ans * 10 + ch - ‘0‘; ch = getchar();}27     if(last == ‘-‘) ans = -ans;28     return ans;29 }30 inline void write(ll x)31 {32     if(x < 0) x = -x, putchar(‘-‘);33     if(x >= 10) write(x / 10);34     putchar(x % 10 + ‘0‘);35 }36 37 int n;38 struct Node39 {40     ll s, e, d;41 }t[maxn];42 43 ll calc(ll x)44 {45     ll ret = 0;46     for(int i = 1; i <= n; ++i)47     {48         if(t[i].s > x) continue;49         ret += (min(x, t[i].e) - t[i].s) / t[i].d + 1;50     }51     return ret;52 }53 54 int main()55 {56     int T = read();57     while(T--)58     {59         n = read(); ll Max = 0;60         for(int i = 1; i <= n; ++i) t[i].s = read(), t[i].e = read(), t[i].d = read(), Max = max(Max, t[i].e);61         ll L = 0, R = Max;62         if(!(calc(R) & 1)) {puts("Poor QIN Teng:( "); continue;}63         while(L < R)64         {65             ll mid = (L + R) >> 1;66             if(calc(mid) & 1) R = mid;67             else L = mid + 1;68         }69         write(L), space, write(calc(L) - calc(L - 1)), enter;70     }71     return 0;72 }

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[Bjwc2008] Qin Teng and teaching evaluation