#include <bits/stdc++.h> using namespace std; #define REP(i,a,b) for (int i = (a); i <= (b); ++i) #define REPD(i,a,b) for (int i = (a); i >= (b); --i) #define FORI(i,n) REP(i,1,n) #define FOR(i,n) REP(i,0,int(n)-1) #define mp make_pair #define pb push_back #define sz(x) int((x).size()) #define dbg(v) cerr << #v << " = " << (v) << endl; #define FOREACH(i,t) for (__typeof(t.begin()) i = t.begin(); i != t.end(); ++i) #define fi first #define se second typedef pair<int,int> pii; typedef vector<int> vi; typedef unsigned long long ll; const ll INF = 10000000000000000000LL; const int MAXN = 1000100; int n,m; int a[MAXN]; char b[MAXN]; ll gcd(ll x, ll y) { ll z; while (y!=0) { z = x%y; x = y; y = z; } return x; } ll lcm(ll x, ll y) { return x/gcd(x,y) * y; } vector<int> cycles[MAXN]; int cycleBalance[MAXN]; int pfxMin[MAXN]; int offsets[MAXN]; vector<int> pfxSum[MAXN]; vector<vector<int> > prefInd[MAXN]; int cyclesNum; int cycleLen; int main() { scanf("%d", &n); FOR(i,n) { scanf("%d", &a[i]); } scanf("%d", &m); scanf("%s", &b); cyclesNum = gcd(n,m); cycleLen = m/gcd(n,m); //compute cycles FOR(i, cyclesNum) { pfxSum[i].pb(0); FOR(j, cycleLen) { char ch=b[((unsigned long long)n*j+i)%m]; if (ch == 'W') cycles[i].pb(1); else cycles[i].pb(-1); if (j==0) pfxSum[i].pb(cycles[i][j]); else pfxSum[i].pb(pfxSum[i][pfxSum[i].size()-1]+cycles[i][j]); if (pfxSum[i][j+1] < pfxMin[i]) pfxMin[i] = pfxSum[i][j+1]; offsets[(n*j+i)%m] = j; } cycleBalance[i] = pfxSum[i][pfxSum[i].size()-1]; FOR(j,cycleLen) { pfxSum[i].pb(pfxSum[i][j+1]+cycleBalance[i]); } prefInd[i].resize(cycleLen*4+1); FOR(j,pfxSum[i].size()) { int val = pfxSum[i][j]; val += 2*cycleLen; prefInd[i][val].pb(j); } } ll best = INF; FOR(i,n) { int cycle = i%cyclesNum; int offset = offsets[i%m]; int findVal = pfxSum[cycle][offset]-a[i]; bool repeat = false; vector<int>::iterator it; if (findVal+2*cycleLen <0 || findVal+2*cycleLen>4*cycleLen) repeat = true; else it = lower_bound(prefInd[cycle][findVal+2*cycleLen].begin(), prefInd[cycle][findVal+2*cycleLen].end(), offset); if (repeat || it == prefInd[cycle][findVal+2*cycleLen].end()) { int newa = a[i] - pfxSum[cycle][offset] + cycleBalance[cycle]; if (cycleBalance[cycle] >= 0) continue; ll res = (i+1) + (unsigned long long)n*(unsigned long long)(cycleLen-offset); ll ile_miesci = ((newa+pfxMin[cycle])/(-1 * cycleBalance[cycle])); res += ile_miesci * (n) * (cycleLen); int findVal2 = (-1)*(newa-ile_miesci*(-1*cycleBalance[cycle])); res += prefInd[cycle][findVal2+2*cycleLen][0]*(unsigned long long)n; if (res < best){ best = res; } } else { ll res = (i+1) + (unsigned long long)(*it-offset-1)*(unsigned long long)n; if (res < best){ best = res; } } } if (best == INF) printf("-1\n"); else printf("%lld\n", best); return 0; }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 | #include <bits/stdc++.h> using namespace std; #define REP(i,a,b) for (int i = (a); i <= (b); ++i) #define REPD(i,a,b) for (int i = (a); i >= (b); --i) #define FORI(i,n) REP(i,1,n) #define FOR(i,n) REP(i,0,int(n)-1) #define mp make_pair #define pb push_back #define sz(x) int((x).size()) #define dbg(v) cerr << #v << " = " << (v) << endl; #define FOREACH(i,t) for (__typeof(t.begin()) i = t.begin(); i != t.end(); ++i) #define fi first #define se second typedef pair<int,int> pii; typedef vector<int> vi; typedef unsigned long long ll; const ll INF = 10000000000000000000LL; const int MAXN = 1000100; int n,m; int a[MAXN]; char b[MAXN]; ll gcd(ll x, ll y) { ll z; while (y!=0) { z = x%y; x = y; y = z; } return x; } ll lcm(ll x, ll y) { return x/gcd(x,y) * y; } vector<int> cycles[MAXN]; int cycleBalance[MAXN]; int pfxMin[MAXN]; int offsets[MAXN]; vector<int> pfxSum[MAXN]; vector<vector<int> > prefInd[MAXN]; int cyclesNum; int cycleLen; int main() { scanf("%d", &n); FOR(i,n) { scanf("%d", &a[i]); } scanf("%d", &m); scanf("%s", &b); cyclesNum = gcd(n,m); cycleLen = m/gcd(n,m); //compute cycles FOR(i, cyclesNum) { pfxSum[i].pb(0); FOR(j, cycleLen) { char ch=b[((unsigned long long)n*j+i)%m]; if (ch == 'W') cycles[i].pb(1); else cycles[i].pb(-1); if (j==0) pfxSum[i].pb(cycles[i][j]); else pfxSum[i].pb(pfxSum[i][pfxSum[i].size()-1]+cycles[i][j]); if (pfxSum[i][j+1] < pfxMin[i]) pfxMin[i] = pfxSum[i][j+1]; offsets[(n*j+i)%m] = j; } cycleBalance[i] = pfxSum[i][pfxSum[i].size()-1]; FOR(j,cycleLen) { pfxSum[i].pb(pfxSum[i][j+1]+cycleBalance[i]); } prefInd[i].resize(cycleLen*4+1); FOR(j,pfxSum[i].size()) { int val = pfxSum[i][j]; val += 2*cycleLen; prefInd[i][val].pb(j); } } ll best = INF; FOR(i,n) { int cycle = i%cyclesNum; int offset = offsets[i%m]; int findVal = pfxSum[cycle][offset]-a[i]; bool repeat = false; vector<int>::iterator it; if (findVal+2*cycleLen <0 || findVal+2*cycleLen>4*cycleLen) repeat = true; else it = lower_bound(prefInd[cycle][findVal+2*cycleLen].begin(), prefInd[cycle][findVal+2*cycleLen].end(), offset); if (repeat || it == prefInd[cycle][findVal+2*cycleLen].end()) { int newa = a[i] - pfxSum[cycle][offset] + cycleBalance[cycle]; if (cycleBalance[cycle] >= 0) continue; ll res = (i+1) + (unsigned long long)n*(unsigned long long)(cycleLen-offset); ll ile_miesci = ((newa+pfxMin[cycle])/(-1 * cycleBalance[cycle])); res += ile_miesci * (n) * (cycleLen); int findVal2 = (-1)*(newa-ile_miesci*(-1*cycleBalance[cycle])); res += prefInd[cycle][findVal2+2*cycleLen][0]*(unsigned long long)n; if (res < best){ best = res; } } else { ll res = (i+1) + (unsigned long long)(*it-offset-1)*(unsigned long long)n; if (res < best){ best = res; } } } if (best == INF) printf("-1\n"); else printf("%lld\n", best); return 0; } |