Portal:
[1]: BZOJ
[2]: Luo Gu
•answer
Define arrays a, b, c respectively represent 'J', 'O', the prefix 'I' and;
To make the interval (L, R] satisfies the condition if and only if a [R] -a [L] = b [R] -b [L] = c [R] -c [L];
那么，由 a[R]-a[L] = b[R]-b[L] ⇔ a[R]-b[R] = a[L]-b[L];
同理，由 b[R]-b[L] = c[R]-c[L] ⇔ b[R]-c[R] = b[L]-c[L];
After pretreatment before the a, b, c array;
For position i, to find whether it contains satisfied before a i -b i = a j -b j && B i -C i = B j -C j position j, and j as small as possible;
How to efficiently find it?
使用 map<pair<int ,int > , int >；
For previously treated location j, the A J -b J and B J -C J into the pair <int, int> each time to find out whether the presence (A I -b I , B I -C I ) i.e. can;
If so, the answer to solving the current, on the contrary, it is added to the map;
•Code