OtterVのrecorder

差分约束 由n个变量和m个他们之间关系的不等式组成的有约束条件的问题。（废话hiahiahia往往可以转换成图论中单源最短路或最长路问题来进行求解，约束条件与其松弛操作类似。·形如d[j]-d[i]>=a[i,j]，可以转化为要满足d[j]>=d[i]+a[i,j]，当d[j]<d[i]+a[i,j]时，为满足条件需要进行松弛操作，d[j]=d[i]+a[i,j]...

K Magical Girl HazeThere are N cities in the country, and M directional roads from u to v(1≤u,v≤n). Every road has a distance ci​. Haze is a Magical Girl that lives in City 1, she can choose no more...