SGU 185 Two shortest short-circuit deletion edge optimization memory + network stream

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Question:

Given n vertices, m records have no direction edge and Edge Weight (no duplicate edge)

Find two shortest paths that do not overlap from 1-N points (the two paths must be the shortest path)

First, we ran with the cost.

Then, the shortest path is optimized, and, and all edges in the shortest path are deleted.

Then you can actually run the network stream, and, at the beginning, it is still mle. Later, we removed the from the adjacent table ,,

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        Using namespace std; # define ll int # define N 402 # define M 121000 # define inf 10737418 # define inf64 1152921504606846976 struct Edge {ll to, cap, nex ;} edge [M * 2]; // note that this must be large enough. Otherwise, re will have reverse arc ll head [N], edgenum; void add (ll u, ll v, ll cap, ll rw = 0) {// if it is a directed edge, add (u, v, cap); if it is a undirected edge, add (u, v, cap, cap); Edge E = {v, cap, head [u]}; edge [edgenum] = E; head [u] = edgenum ++; Edge E2 = {u, rw, head [v]}; edge [edgenum] = E2; head [v] = edgenum ++;} ll sign [N]; bool BFS (ll from, ll) {memset (sign,-1, sizeof (sign); sign [from] = 0; queue
       
         Q; q. push (from); while (! Q. empty () {int u = q. front (); q. pop (); for (ll I = head [u]; I! =-1; I = edge [I]. nex) {ll v = edge [I]. to; if (sign [v] =-1 & edge [I]. cap) {sign [v] = sign [u] + 1, q. push (v); if (sign [to]! =-1) return true ;}}return false;} ll Stack [N], top, cur [N]; ll Dinic (ll from, ll) {ll ans = 0; while (BFS (from, to) {memcpy (cur, head, sizeof (head); ll u = from; top = 0; while (1) {if (u = to) {ll flow = inf, loc; // loc indicates the minimum cap edge in the Stack for (ll I = 0; I <top; I ++) if (flow> edge [Stack [I]. cap) {flow = edge [Stack [I]. cap; loc = I ;}for (ll I = 0; I <top; I ++) {edge [Stack [I]. c Ap-= flow; edge [Stack [I] ^ 1]. cap + = flow;} ans + = flow; top = loc; u = edge [Stack [top] ^ 1]. to;} for (ll I = cur [u]; I! =-1; cur [u] = I = edge [I]. nex) // cur [u] indicates the subscript if (edge [I] of the edge where the u is located. cap & (sign [u] + 1 = sign [edge [I]. to]) break; if (cur [u]! =-1) {Stack [top ++] = cur [u]; u = edge [cur [u]. to;} else {if (top = 0) break; sign [u] =-1; u = edge [Stack [-- top] ^ 1]. to ;}} return ans;} void init () {memset (head,-1, sizeof head); edgenum = 0;} ll dis [N]; ll n, m; ll mp [401] [401]; bool inq [N]; void spfa (int from, int to) {for (int I = 1; I <= n; I ++) dis [I] = inf; memset (inq, 0, sizeof inq); dis [from] = 0; queue
        
          Q; q. push (from); inq [to] = 1; while (! Q. empty () {int u = q. front (); q. pop (); inq [u] = 0; for (int I = 1; I <= n; I ++) if (dis [I]> dis [u] + mp [u] [I]) {dis [I] = dis [u] + mp [u] [I]; if (! Inq [I]) inq [I] = 1, q. push (I) ;}} void dfs (ll u, ll fa) {if (u = n) {printf ("% d \ n", u ); return;} else printf ("% d", u); for (ll I = head [u]; ~ I; I = edge [I]. nex) {if (edge [I ^ 1]. cap! = 1 | (I & 1) continue; ll v = edge [I]. to; if (v = fa) continue; edge [I ^ 1]. cap = 0; dfs (v, u); return ;}} int main () {ll u, v, cost; while (~ Scanf ("% d", & n, & m) {init (); for (int I = 1; I <= n; I ++) for (int j = 1; j <= n; j ++) mp [I] [j] = inf; while (m --) {scanf ("% d", & u, & v, & cost ); mp [u] [v] = mp [v] [u] = min (mp [u] [v], cost);} spfa (1, n ); if (dis [n] = inf) {puts ("No solution"); continue;} for (ll I = 1; I <= n; I ++) for (ll j = 1; j <= n; j ++) if (mp [I] [j]! = Inf & dis [j] = mp [I] [j] + dis [I]) add (I, j, 1); add (n, n + 1, 2); ll DIS = Dinic (1, n + 1); if (DIS! = 2) {puts ("No solution"); continue;} else {dfs (); dfs () ;}} return 0 ;} /* 4 6 1 2 1 1 3 1 3 3 3 3 4 2 2 4 1 1 1 1 3 1 3 1 3 3 3 3 3 1 2 2 2 2 3 3 1 3 1 */