!4638 fix core when use weighted_random_sampler

Merge pull request !4638 from yanghaitao/yht_fix_weighted_sampler

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/sampler/weighted_random_sampler.cc

@@ -44,6 +44,13 @@ Status WeightedRandomSampler::InitSampler() {
   }
   CHECK_FAIL_RETURN_UNEXPECTED(num_rows_ > 0 && num_samples_, "num_samples & num_rows need to be positive");
   CHECK_FAIL_RETURN_UNEXPECTED(samples_per_buffer_ > 0, "samples_per_buffer<=0\n");
+  if (weights_.size() > static_cast<size_t>(num_rows_)) {
+    return Status(StatusCode::kUnexpectedError, __LINE__, __FILE__,
+                  "number of samples weights is more than num of rows. Might generate id out of bound OR other errors");
+  }
+  if (!replacement_ && (weights_.size() < static_cast<size_t>(num_samples_))) {
+    RETURN_STATUS_UNEXPECTED("Without replacement, sample weights less than numSamples");
+  }
 
   // Initialize random generator with seed from config manager
   rand_gen_.seed(GetSeed());