{"trustable":false,"sections":[{"title":"","value":{"format":"HTML","content":"\n \u003cdiv class\u003d\"ptx\" lang\u003d\"en-US\"\u003e\n FJ\u0027s cows really hate getting wet so much that the mere thought of getting caught in the rain makes them shake in their hooves. They have decided to put a rain siren on the farm to let them know when rain is approaching. They intend to create a rain evacuation plan so that all the cows can get to shelter before the rain begins. Weather forecasting is not always correct, though. In order to minimize false alarms, they want to sound the siren as late as possible while still giving enough time for all the cows to get to some shelter. \n \u003cbr\u003e \n \u003cbr\u003eThe farm has F (1 \u0026lt;\u003d F \u0026lt;\u003d 200) fields on which the cows graze. A set of P (1 \u0026lt;\u003d P \u0026lt;\u003d 1500) paths connects them. The paths are wide, so that any number of cows can traverse a path in either direction. \n \u003cbr\u003e \n \u003cbr\u003eSome of the farm\u0027s fields have rain shelters under which the cows can shield themselves. These shelters are of limited size, so a single shelter might not be able to hold all the cows. Fields are small compared to the paths and require no time for cows to traverse. \n \u003cbr\u003e \n \u003cbr\u003eCompute the minimum amount of time before rain starts that the siren must be sounded so that every cow can get to some shelter.\n \u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\n \u003cdiv class\u003d\"ptx\" lang\u003d\"en-US\"\u003e\n * Line 1: Two space-separated integers: F and P \n \u003cbr\u003e \n \u003cbr\u003e* Lines 2..F+1: Two space-separated integers that describe a field. The first integer (range: 0..1000) is the number of cows in that field. The second integer (range: 0..1000) is the number of cows the shelter in that field can hold. Line i+1 describes field i. \n \u003cbr\u003e \n \u003cbr\u003e* Lines F+2..F+P+1: Three space-separated integers that describe a path. The first and second integers (both range 1..F) tell the fields connected by the path. The third integer (range: 1..1,000,000,000) is how long any cow takes to traverse it.\n \u003c/div\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\n \u003cdiv class\u003d\"ptx\" lang\u003d\"en-US\"\u003e\n * Line 1: The minimum amount of time required for all cows to get under a shelter, presuming they plan their routes optimally. If it not possible for the all the cows to get under a shelter, output \"-1\".\n \u003c/div\u003e"}},{"title":"Sample Input","value":{"format":"HTML","content":"\u003cpre class\u003d\"sio\"\u003e3 4\n7 2\n0 4\n2 6\n1 2 40\n3 2 70\n2 3 90\n1 3 120\u003c/pre\u003e"}},{"title":"Sample Output","value":{"format":"HTML","content":"\u003cpre class\u003d\"sio\"\u003e110\u003c/pre\u003e"}},{"title":"Hint","value":{"format":"HTML","content":"\n \u003cdiv class\u003d\"ptx\" lang\u003d\"en-US\"\u003e\n OUTPUT DETAILS: \n \u003cbr\u003e \n \u003cbr\u003eIn 110 time units, two cows from field 1 can get under the shelter in that field, four cows from field 1 can get under the shelter in field 2, and one cow can get to field 3 and join the cows from that field under the shelter in field 3. Although there are other plans that will get all the cows under a shelter, none will do it in fewer than 110 time units.\n \u003c/div\u003e"}},{"title":"Translation","value":{"format":"HTML","content":"给定一个无向图,点i处有Ai头牛,点i处的牛棚能容纳Bi头牛,求一个最短时间T使得在T时间内所有的牛都能进到某一牛棚里去。(1 \u003c\u003d N \u003c\u003d 200, 1 \u003c\u003d M \u003c\u003d 1500, 0 \u003c\u003d Ai \u003c\u003d 1000, 0 \u003c\u003d Bi \u003c\u003d 1000, 1 \u003c\u003d Dij \u003c\u003d 1,000,000,000)"}}]}