T1 "dichotomy"
22 min violence enumerated set of points, and then found that DP [state] can not afford the time and space
Then consider the other hand, said the casual working to ensure ans <= 1e9 then obviously the show is a half,
First of all k> 0 must be monotonically increasing, and that there is a negative it?
Somewhere I feel this problem can not be so water could not be guaranteed monotonic,
And then added a third, tune for a long time, spent a total of two and a half hours, so two questions did not tune out
Finished listening to DeepinC chiefs talked about why monotonous
First chk (0) what, if they meet directly puts ( "0")
Otherwise, when the next half of the k <0 the set point can never be a contribution and then s
Was not affected chk, monotonically rising
T2 "Fenwick tree."
As the final output just $ X_1%, then it is natural to think of other things represented by $ X_1 $
Then the equation for the newly added, the situation will be as follows: $ X_u + X_v = t $ or $ X_u + X_v == t-2 * X_1 $ or discussed $ X_u + X_v == t + 2 * X_1 $ separated
Modifications: change can be found for each value of w,