ソースコード
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;
public class Main {
static InputStream is;
static PrintWriter out;
static String INPUT = "";
static void solve() {
int n = ni(), m = ni(), K = ni();
int[] from = new int[m];
int[] to = new int[m];
int[] w = new int[m];
for(int i = 0;i < m;i++){
from[i] = ni()-1;
to[i] = ni()-1;
w[i] = ni();
}
int[][][] g = packWU(n, from, to, w);
int[][] hs = new int[K][];
for(int i = 0;i < K;i++){
hs[i] = new int[]{ni()-1, ni()};
}
long[] td = new long[n];
int O = 100005;
Arrays.fill(td, Long.MAX_VALUE / 2);
MinHeapL q = new MinHeapL(n);
for(int[] h : hs){
q.add(h[0], td[h[0]] = O - h[1]);
}
while(q.size() > 0){
int cur = q.argmin();
q.remove(cur);
for(int[] e : g[cur]){
int next = e[0];
long nd = td[cur] + e[1];
if(nd < td[next]){
td[next] = nd;
q.update(next, nd);
}
}
}
int ct = 0;
for(int i = 0;i < n;i++){
if(td[i] <= O){
ct++;
}
}
out.println(ct);
}
public static class MinHeapL {
public long[] a;
public int[] map;
public int[] imap;
public int n;
public int pos;
public static long INF = Long.MAX_VALUE;
public MinHeapL(int m)
{
n = Integer.highestOneBit((m+1)<<1);
a = new long[n];
map = new int[n];
imap = new int[n];
Arrays.fill(a, INF);
Arrays.fill(map, -1);
Arrays.fill(imap, -1);
pos = 1;
}
public long add(int ind, long x)
{
int ret = imap[ind];
if(imap[ind] < 0){
a[pos] = x; map[pos] = ind; imap[ind] = pos;
pos++;
up(pos-1);
}
return ret != -1 ? a[ret] : x;
}
public long update(int ind, long x)
{
int ret = imap[ind];
if(imap[ind] < 0){
a[pos] = x; map[pos] = ind; imap[ind] = pos;
pos++;
up(pos-1);
}else{
a[ret] = x;
up(ret);
down(ret);
}
return x;
}
public long remove(int ind)
{
if(pos == 1)return INF;
if(imap[ind] == -1)return INF;
pos--;
int rem = imap[ind];
long ret = a[rem];
map[rem] = map[pos];
imap[map[pos]] = rem;
imap[ind] = -1;
a[rem] = a[pos];
a[pos] = INF;
map[pos] = -1;
up(rem);
down(rem);
return ret;
}
public long min() { return a[1]; }
public int argmin() { return map[1]; }
public int size() { return pos-1; }
private void up(int cur)
{
for(int c = cur, p = c>>>1;p >= 1 && a[p] > a[c];c>>>=1, p>>>=1){
long d = a[p]; a[p] = a[c]; a[c] = d;
int e = imap[map[p]]; imap[map[p]] = imap[map[c]]; imap[map[c]] = e;
e = map[p]; map[p] = map[c]; map[c] = e;
}
}
private void down(int cur)
{
for(int c = cur;2*c < pos;){
int b = a[2*c] < a[2*c+1] ? 2*c : 2*c+1;
if(a[b] < a[c]){
long d = a[c]; a[c] = a[b]; a[b] = d;
int e = imap[map[c]]; imap[map[c]] = imap[map[b]]; imap[map[b]] = e;
e = map[c]; map[c] = map[b]; map[b] = e;
c = b;
}else{
break;
}
}
}
}
public static int[][][] packWU(int n, int[] from, int[] to, int[] w) {
int[][][] g = new int[n][][];
int[] p = new int[n];
for (int f : from)
p[f]++;
for (int t : to)
p[t]++;
for (int i = 0; i < n; i++)
g[i] = new int[p[i]][2];
for (int i = 0; i < from.length; i++) {
--p[from[i]];
g[from[i]][p[from[i]]][0] = to[i];
g[from[i]][p[from[i]]][1] = w[i];
--p[to[i]];
g[to[i]][p[to[i]]][0] = from[i];
g[to[i]][p[to[i]]][1] = w[i];
}
return g;
}
public static void main(String[] args) throws Exception {
long S = System.currentTimeMillis();
is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
out = new PrintWriter(System.out);
solve();
out.flush();
long G = System.currentTimeMillis();
tr(G - S + "ms");
}
private static boolean eof() {
if (lenbuf == -1)
return true;
int lptr = ptrbuf;
while (lptr < lenbuf)
if (!isSpaceChar(inbuf[lptr++]))
return false;
try {
is.mark(1000);
while (true) {
int b = is.read();
if (b == -1) {
is.reset();
return true;
} else if (!isSpaceChar(b)) {
is.reset();
return false;
}
}
} catch (IOException e) {
return true;
}
}
private static byte[] inbuf = new byte[1024];
public static int lenbuf = 0, ptrbuf = 0;
private static int readByte() {
if (lenbuf == -1)
throw new InputMismatchException();
if (ptrbuf >= lenbuf) {
ptrbuf = 0;
try {
lenbuf = is.read(inbuf);
} catch (IOException e) {
throw new InputMismatchException();
}
if (lenbuf <= 0)
return -1;
}
return inbuf[ptrbuf++];
}
private static boolean isSpaceChar(int c) {
return !(c >= 33 && c <= 126);
}
private static int skip() {
int b;
while ((b = readByte()) != -1 && isSpaceChar(b))
;
return b;
}
private static double nd() {
return Double.parseDouble(ns());
}
private static char nc() {
return (char) skip();
}
private static String ns() {
int b = skip();
StringBuilder sb = new StringBuilder();
while (!(isSpaceChar(b))) { // when nextLine, (isSpaceChar(b) && b != '
// ')
sb.appendCodePoint(b);
b = readByte();
}
return sb.toString();
}
private static char[] ns(int n) {
char[] buf = new char[n];
int b = skip(), p = 0;
while (p < n && !(isSpaceChar(b))) {
buf[p++] = (char) b;
b = readByte();
}
return n == p ? buf : Arrays.copyOf(buf, p);
}
private static char[][] nm(int n, int m) {
char[][] map = new char[n][];
for (int i = 0; i < n; i++)
map[i] = ns(m);
return map;
}
private static int[] na(int n) {
int[] a = new int[n];
for (int i = 0; i < n; i++)
a[i] = ni();
return a;
}
private static int ni() {
int num = 0, b;
boolean minus = false;
while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
;
if (b == '-') {
minus = true;
b = readByte();
}
while (true) {
if (b >= '0' && b <= '9') {
num = num * 10 + (b - '0');
} else {
return minus ? -num : num;
}
b = readByte();
}
}
private static long nl() {
long num = 0;
int b;
boolean minus = false;
while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
;
if (b == '-') {
minus = true;
b = readByte();
}
while (true) {
if (b >= '0' && b <= '9') {
num = num * 10 + (b - '0');
} else {
return minus ? -num : num;
}
b = readByte();
}
}
private static void tr(Object... o) {
if (INPUT.length() != 0)
System.out.println(Arrays.deepToString(o));
}
}